Some standard content:
Military Standard for Electronic Industry of the People's Republic of China FL5911
Metal Oxide
SJ20025—92
Generic specification for gases
snesors of metal-oxide semiconductor1992-02-01 Issued
China Electronics Industry Corporation
1992-05-01 Implementation
1 Scope
Subject Content
Scope of Application
1.3 Classification
1.4 Product Quality Mark
Referenced Documents
General Requirements
Priority Order
3.3 Identification||t t||Product quality assurance requirements
Design, structure and materials.
Process requirements
Performance of gas sensors
Environmental requirements of gas sensors
Appearance quality…·
Quality assurance regulations
Inspection qualifications
Procedures to be performed for batches that have been in stock for more than 6 months Inspection classification
Inspection conditions and methods
Appraisal inspection
Quality I Conformity test…
Packaging test·
4.9 Maintenance of qualified identification
5 Preparation for delivery
5.1 Packaging requirements..
5.2 Storage requirements
5.3 Transport requirements…
6 Notes
Intended use
（12)
（12)
（12)
6.2 Contents of ordering documents
Detailed specifications
Identification approval…
Appendix A Product assurance procedures and certification requirements for specific production lines and quality laboratories (supplement) Appendix B
Product variety identification procedures (supplement)
1 Scope
People's Republic of China Electronic Industry Military Standard General Specification for Metal Oxide Semiconductor Gas Sensors
snesors 1.1 Subject Content
SJ20025—92
This specification specifies the general requirements for quality assurance, inspection rules, packaging, storage and transportation of military metal oxide semiconductor gas sensors (hereinafter referred to as gas sensors or products). Specific requirements and characteristics are specified in the corresponding military detailed specifications (hereinafter referred to as detailed specifications).
1.2 Scope of Application
This specification applies to metal oxide semiconductor gas sensors for military equipment, and other gas sensors and civilian gas sensors can also be used as a reference.
1.3 Classification
Gas sensors should be classified according to the following regulations:
A Sintered type
B Thin film type
C Thick film type
D Mixed type
1.4 Product Quality Mark
All products approved by the appraisal agency and meeting the requirements of this specification and the corresponding detailed specifications shall use the letter G as the quality mark. Reference documents
GB191---73
GB2828—87
GB2829--87
GB4475—84
GB7408-87
CJB360--87
SJ1155--82
SI20026—92
SJ2007992
Packaging storage and transportation graphic signs
Batch inspection counting sampling procedures and sampling tables (applicable to continuous batch inspection) Periodic inspection counting sampling procedures and sampling tables (applicable to production process stability inspection) Sensitive Component terminology
Week number
Test methods for electronic and electrical components
Nomenclature of sensitive component models
Test methods for metal oxide semiconductor gas sensors Test methods for metal oxide semiconductor gas sensors Issued by China Electronics Industry Corporation on February 1, 1992 and implemented on May 1, 1992
3 Requirements
3.1 General requirements
SJ20025—92
Product requirements shall comply with this specification and relevant detailed specifications. When the term "specified" or "according to regulations" is used in this specification without citing the source, it refers to the detailed specifications. When producing products according to this specification and detailed specifications, a product certificate issued by an appraisal agency must be obtained first. Only products that have been inspected and meet all the requirements specified in the corresponding detailed specifications and this specification can be marked with the G mark. 3.2 Order of precedence
If there is a conflict between the requirements of this specification and the detailed specifications or other relevant documents, the authority of the documents shall be arranged in the following order of precedence:
Detailed specifications,
This specification:
Related documents in Chapter 2.
3.3 Identification
The product varieties provided by the manufacturer in accordance with this specification shall be product varieties approved by the identification agency and issued with product certificates.
The identification and approval procedures for product varieties are as follows: a. The identification agency shall review and approve the product quality assurance procedures established by the manufacturer for the product variety in accordance with the requirements of Appendix A;
The identification agency shall review and certify the specific production lines and quality laboratories of the manufacturer in accordance with the requirements of Appendix A; b.
The identification agency shall issue certificates of conformity to the product varieties approved by the manufacturer. c.
3.4 Product quality assurance requirements
The products provided in accordance with this specification shall comply with the quality assurance provisions in Chapter 4 of this specification and be delivered in accordance with the provisions in Chapter 5. The quality mark G may only be used on products that meet these requirements. 3.4.1 Summary of requirements
Table 1 summarizes the requirements for product quality assurance. Table 1 Product quality assurance requirements
Product quality assurance procedures and investigations
Manufacturing plant production line and quality laboratory certificationb.
Qualification inspection and testing
Inspection lot
Traceability
Quality-Consistency Inspection
Group A (per batch)
h. Group B (each batch)
Group C (cycle)
3.4.2 Product quality assurance procedures
Corresponding articles
3.4.2 and Appendix A
3.4.2.2 and Appendix A
4.6 and Table 3
4.7.1 and Table 4
4.7.2 and Table 5
4.7.3 and Table 6
SJ20025-92
As a prerequisite for the certification of the manufacturer's specific production line and the identification of product varieties, the manufacturer shall establish and implement the product quality assurance procedures specified in Appendix A. The manufacturer shall also submit the procedure plan for approval in accordance with the provisions of Appendix A (see Article A2.1.2) and prepare for the identification agency to investigate the manufacturer's specific production line. 3.4.2.1 Changes to procedure documents
After the manufacturer's product assurance procedures are approved, the manufacturer shall not make any changes to the product design, process, materials or monitoring without the approval of the certification body.
3.4.2.2 Specific production line and quality laboratory certification requirements The certification body shall conduct a comprehensive inspection of the manufacturer's specific production line and quality laboratory in accordance with the requirements of 3.4.2 and the provisions of A3.1 and A3.2 of Appendix A. If the inspection is qualified, the factory will be issued a specific production line certification certificate and a quality laboratory certification certificate (specifying the types of products allowed to undergo quality consistency inspection). The certificate is valid for three years. The manufacturer shall complete the product variety identification within the first year of the certificate's validity period. The certification body shall conduct regular (three-year cycle) inspections and spot checks on the manufacturer's product quality assurance procedures and program plans, specific production lines and quality laboratories to ensure their implementation and consistency. A notice of extending the validity period of the certification certificate for three years will be issued to the manufacturer's specific production line and quality laboratory that have passed the regular inspection. If the manufacturer's specific production line and quality laboratory are not regularly inspected after three years, the validity period of the certification certificate will usually not be extended. The appraisal agency should notify the manufacturer that the validity period of the certification certificate will not be extended. 3.4.2.2.1: Certification requirements for quality laboratories If the relevant testing agencies or provincial and municipal testing agencies meet the inspection requirements of this specification and the provisions of Article A3.2 of Appendix A, they can apply to the appraisal agency for quality laboratory certification and obtain a certification certificate (see Article 3.4.2.2). If the manufacturer only certifies a specific production line and does not have a certified quality laboratory, the identification inspection and quality consistency inspection of the factory's product varieties can be entrusted to the relevant certified testing agencies or other factory quality laboratories. 3.4.2.2.2 Cancellation of the certification certificate
The certification body may cancel the certification certificate of a specific production line and quality laboratory in any of the following circumstances: a. Within the validity period of the certification certificate, products that meet the requirements of this specification are not produced on the specific production line; b. The requirements of this specification are not met;
c. During regular inspections or spot checks, the specific production line and quality laboratory fail to meet the requirements of Appendix A and continue to fail to meet the requirements within the specified period;
d. The representative of the certification body is not allowed to inspect the process and review the certification documents required by Chapter A3 of Appendix A. 3.4.2.2.3 Restoration of the certification certificate
The certification certificate may be restored when the manufacturer or test agency has re-met and fulfilled all the requirements specified in this specification, or has met the requirements set by the certification body to correct defects and ensure compliance with the certification. 3.4.3 Product variety identification
The manufacturer's acquisition of a specific production line certification certificate only means that it has the conditions to produce G-marked products. The manufacturer also needs to conduct variety identification for the product varieties it is preparing to provide. If the variety is qualified, the manufacturer can put the G mark on the product after approval by the appraisal agency and obtaining the product certificate. The product variety appraisal procedure shall be in accordance with the provisions of Appendix B, and the appraisal inspection shall be carried out in accordance with the requirements of Article 4.5.
3.4.4 Changes to the Approved Product
After the product appraisal is approved, if the manufacturer intends to make changes to the product or product assurance procedure that may affect the performance, quality, appearance, reliability or interchangeability, it shall notify the appraisal agency. For all affected program documents, the design, materials and processes of the product must be changed in accordance with the provisions of the change control procedures in Articles A2.1.2 and A2.1.1.5 of Appendix A. This notification shall include a complete description of the change process, and a test plan shall be proposed to prove that such changes will not have a harmful effect on the performance, quality, reliability or interchangeability of the product, and that the changed product will continue to meet the specification requirements. The appraisal agency shall review the change instructions and test plans proposed by the manufacturer and make comments on the test. The manufacturer shall conduct the test according to the approved test plan and shall submit the complete test results to the appraisal agency for review. If the manufacturer obtains the approval of the appraisal agency, it can produce products according to the changed documents and submit them for quality consistency inspection. Without the consent of the appraisal agency, products produced according to the original design can no longer be submitted for quality consistency inspection. Finished products manufactured according to the original approved design in stock or during testing (inspection batches with designated identification codes) will remain valid unless the manufacturer is required to correct or eliminate a verified design defect by changing the design. Typical changes that follow the above requirements are changes to the basic design. For example: a.
Sensitive materials;
Dopant materials or doping processes;
Structure of carriers:
Mask design or redesign;
Passivation materials or processes:
Materials, methods or positions for connecting the die and the base; Heater materials and dimensions:
Materials and dimensions of electrode leads;
Shell (including mesh cover, base, lead-out terminals, endpoints, etc.) structure and materials or inner cavity geometry; Packaging technology.
3.5 Design, structure and materials
3.5.1 Design
When designing products, the manufacturer should consider the following requirements: This specification and detailed specifications:
Field use requirements;
Feedback from users of similar products produced by our factory in recent years; c.
Test and failure analysis data of samples and feedback from users. 3.5.2 Structure
The structure of the product shall comply with the requirements of the detailed specifications. Alloy welding or spot ultrasonic welding shall be used when connecting the tube core and the base. Silver paste bonding is prohibited. Explosion-proof metal mesh covers shall be used for flammable and explosive gas-sensitive components. 3.5.3 Materials
The materials of the product shall comply with the provisions of the detailed specifications and relevant specifications. 3.5.3.1 Anti-mildew materials
The external parts of the product shall be materials that do not naturally breed mildew. 3.5.3.2 External metal
The external metal surface of the product shall be corrosion-resistant or corrosion-resistant after electroplating or painting. 3.5.3.3 Material restrictions
The surface of the housing or package shall be smooth and shall not have any dents or burrs. External parts, plating or coatings shall be free of bubbles, cracks, softening, deformation or defects that have a harmful effect on the storage, operation or environmental adaptability of the components. The size of the external housing shall not be increased due to the use of organic or polymer materials. Without the consent of the appraisal agency, desiccant shall not be used inside the shell, nor shall polymer materials be filled. 3.6 Process requirements
The manufacturer shall manufacture the product in accordance with the best product design and perfect engineering practice and in accordance with the requirements of this specification. 4
3.6.1 Process
SJ20025—92
The manufacturer shall conduct process design and process experiments, select reasonable process approaches, formulate process specifications and process quality inspection standards, and operators shall strictly follow the regulations. 3.7 Performance characteristics of gas sensors
The performance test of gas sensors shall be carried out in accordance with the provisions of SJ20026, and its test conditions and limit values shall comply with the provisions of the detailed specifications. For parameter tests not specified in SJ20026, the test methods shall be given in the appendix of the detailed specifications. 3.8 Environmental requirements for gas sensors
The environmental requirements for gas sensors shall be carried out in accordance with the provisions of SJ20079, and its details and inspection requirements shall meet the requirements of the detailed specifications.
3.9 Marking
3.9.1 Marking on the product
Each product shall have the following markings upon delivery: terminal identification (see 3.9.4);
Product model (see 3.9.5);
Product quality mark G (see 3.9.6); manufacturer's name, code or trademark (see 3.9.7); inspection batch identification code (see 3.9.8); f. product serial number (see 3.9.9).
When area does not allow, the detailed specification shall give the minimum requirements in the above order of priority. 3.9.2 Special markings
If the manufacturer uses any special markings, they must not hinder or obscure the markings required in 3.9.1. The product manual shall include an explanation of the special markings. 3.9.3 The overall package (or packaging box) shall have the following marks: a.
All marks listed in 3.9.1 except the terminal identification mark; Detailed specification number:
Inspection and re-inspection (if re-inspection is carried out) date; Inspector's stamp;
Others.
3.9.4 Terminal identification
The terminal identification shall be specified in the detailed specification. 3.9.5 Product model
Each product shall be marked with its model in accordance with SJ1155. 3.9.6 Product quality mark G
Various models of gas sensors that meet the requirements of this specification and the corresponding detailed specifications shall have the product quality mark G. If the contract or agreement allows or requires modifications to this specification or the corresponding detailed specifications (except for the lead length, material or coating of the component leads), any component delivered under such a contract or agreement shall not use the G mark. The G mark is the mark of components approved by the certification body and issued with a product certificate. The verifiable data will be retained by the manufacturer for no less than ten years. When necessary, these test data will help the representatives of the certification body to conduct on-site inspections. When the batch inspection fails, the manufacturer shall remove or paint over the G mark from the test sample and all the components represented by the sample within 30 days. 3.9.7 Manufacturer's name, code, and trademark
SJ20025-92
The manufacturer's name, code or trademark shall be on the qualified gas sensor so that the manufacturer can be easily identified according to the mark. 3.9.8 Inspection batch identification code
The inspection batch identification code shall comply with the provisions of GB7408 and shall be expressed by adding the last two digits of the year before the week number (for example: 8305-the 5th week of 1983). When more than one batch of products are submitted for quality consistency inspection in the same week, a capital English letter shall be added to the identification code of the above batch as a suffix letter to identify the batch. 3.9.9 Serial Numbering
When required, gas sensors in the inspection lot shall be marked and documented with consecutive serial numbers. 3.9.10 Marking Option
In addition to serial numbering, the manufacturer has the right to decide whether to mark the entire inspection lot or the inspected samples. If the manufacturer chooses to mark only the samples, the following procedures should be followed: The samples should be marked before the quality consistency inspection or the identification inspection: a.
b. When the inspection is completed, the marking of the samples should be checked to see if it meets the requirements of Section 3.9.1; then the inspection lot represented by the quality consistency inspection sample should be marked and any specified appearance and mechanical c.
Inspection;
The marking materials and processes used for the inspection batch and the marking materials and processes used for the inspection samples shall comply with the same specifications.
3.10 Appearance quality
The gas sensor shall be processed in a way that ensures consistent quality, and its base and mesh cover shall have a smooth surface and no cracks. The explosion-proof metal mesh shall be made of double-layer stainless steel with a mesh size of 80 or above, and shall be neat, without damage or falling off, and the lead wire shall be firm and not loose. 4 Quality Assurance Provisions
4.1 Inspection Responsibilities
Unless otherwise specified in the contract or order, the manufacturer shall be responsible for implementing all inspection requirements specified in this specification. Unless otherwise specified in the contract or order, the manufacturer may use its own equipment or any other equipment suitable for completing the inspection requirements specified in this specification as long as the superior appraisal agency approves it. When the user or the superior appraisal agency deems it necessary, it has the right to inspect any inspection items described in this specification to ensure that the products and services meet the specified requirements. 4.2 Procedures to be followed for batches stored for more than 6 months Products that have passed the quality consistency test and have been stored at the manufacturer for more than 6 months shall be re-tested by the manufacturer according to all the specified inspection requirements before delivery (the delivered products shall have a quality consistency test date or a re-test date not exceeding 6 months apart). In the event of a batch failure during the re-test, 100% inspection of all failure parameters and characteristics of the batch shall be carried out. All gas sensors that fail in any of these tests shall be removed from the batch and rejected, and the product quality mark and military mark J shall be removed or painted over within 30 days. The remaining gas sensors shall retain the original batch identification code. The re-test date mark shall be in accordance with the provisions of 3.9.3. 4.3 Inspection classification
Inspections shall be classified as follows:
a. Identification inspection;
b. Screening;
Quality consistency inspection;
d. Packaging inspection.
4.3.1 Production batch
A production batch shall consist of gas sensors manufactured on the same production line using the same design, process, material and equipment. —6
4.3.2 Inspection batch
SJ20025—92
All gas sensors submitted by the manufacturer for identification or quality consistency inspection within a certain period of time shall be determined to determine whether they meet the requirements of the detailed specification and this specification.
An inspection batch may consist of one production batch or several production batches manufactured under essentially the same conditions (materials, processes, equipment, etc.). In an inspection batch consisting of several production batches, the interval between the first and last production batches submitted shall not exceed one month.
4.3.3 Traceability
All gas sensors delivered in accordance with this specification shall be identifiable (see 3.9.1) and shall be traced through the inspection batch identification code, product inspection and inspection batch records. 4.3.4 Resubmission of batches
Resubmission of batches shall be separated from new batches and shall be clearly identifiable as resubmissions. When any batch submitted for identification or quality consistency inspection fails to meet any of the requirements of the identification inspection groups or the inspection of groups A, B or C, the failed group may be resubmitted once using the tightened inspection regulations. Resubmission using the tightened inspection regulations is permitted if the failure analysis conducted determines the failure mechanism of the previously submitted gas sensor and determines that the failure is caused by the following reasons. a. Rescreening of defects that can be effectively screened out by the entire batch; b. Random defects that are not caused by basic design errors or basic process procedures of the product. The analysis of the failed product shows that the failure mechanism is a poor basic process procedure, a basic design error or a defect that cannot be screened out. In all these cases, the batch shall not be resubmitted. 4.4 Inspection conditions and methods
4.4.1 Inspection conditions
The inspection conditions shall comply with the provisions of SJ20026 and SJ20079. Specific conditions and implementation details shall comply with the requirements of the corresponding detailed specifications.
4.4.2 Alternative test methods
If the manufacturer can prove that the test methods or circuits specified in SJ20026 and SJ20079 are replaced by other test methods or circuits without relaxing the requirements of this specification, and document the supervision and calibration of the test equipment, and provide a schematic diagram of the test equipment or circuit for review. With the consent of the user and the superior appraisal agency, the alternative test or circuit may be used. 4.4.3 Procedures for test equipment failure or operator error If it is confirmed that the failure of the gas sensor is caused by test equipment failure or operator error, such failure should be recorded in the test record. The test record should be submitted to the representative of the supervisory department together with a complete explanation of why it is confirmed that the test failure cannot be judged as caused by product performance degradation or poor structure. If the supervisory representative decides that it cannot be judged as a failure, it will agree to scrap these products. Then the same number of replacement products can be drawn from the same inspection batch to supplement the samples. The replacement product shall be subjected to all tests to which the scrapped product was subjected before failure and to the specified tests to which the scrapped product was not subjected before failure.
4.4.4 Precautions
Sufficient precautions shall be taken during inspection to prevent moisture condensation on gas sensors, except where moisture is an element of the test during the test. Precautions shall also be taken to prevent damage due to heat when gas sensors require welding. 4.5 Qualification Inspection
4.5.1 Batch Size
The size of the qualification inspection batch shall be extracted from the production line by the manufacturer and shall be produced in the production line using normal equipment and processes. The size of the inspection batch shall be at least twice the number of samples required for the qualification inspection. 7
4.5.2 Samples and identification of samples
SJ20025—92
The number of samples of gas sensors submitted for identification and inspection is 70. The supervisory representative of the identification agency can mark each component that needs to be tested for identification, or entrust others to mark it, so as to separate these components from those that are not prepared for identification and inspection (see Article 3.9.10).
4.5.3 Identification and inspection
The manufacturer shall identify the component varieties according to the requirements of Article 3.4.3 before using the G mark on the delivered components. The identification and inspection shall be carried out in the quality laboratory certified by the identification agency in accordance with the provisions of this specification and Appendix B. The samples shall be inspected for identification according to the items and sequence specified in Table 2. All samples except those in Group 1A shall be inspected in Group 1, and then 70 samples shall be taken from Group 1 and divided into 8 groups for separate inspection according to the provisions of Table 2. Table 2 Identification inspection
Inspection items
External gauge and mechanical inspection
Resistance in clean air
Detection concentration range
Resistance in detection gas
Sensitivity
Resolution
Characteristic concentration ratio
Response time
Recovery time
Weldability
Short-term load
Low-temperature storage
High-temperature storage
Heating power
Lead terminal strength
Environmental temperature coefficient
Environmental humidity coefficient
Temperature cycle
Long-term load
Acceleration
Corrosion resistance
Method code
As specified
Sample size
Number of failures
Total allowablebZxz.net
Number of failures
SJ20025--92
Note: ① If a single or multiple tests of the same gas sensor in the same test group fail, they will only be treated as individual failures; ② Only when the marking is incorrect, incomplete or unclear will it be considered as failure: ③ Group 1A samples will not be subjected to Group 1 tests. 4.5.4 Final test
Electrical characteristics should be tested and recorded before the start of the identification inspection and after the completion of these tests. 4.5.5 Submission of data
The data of all tests should be recorded in detail to verify the test procedures and test conditions adopted. 4.5.6 Release of the batch
If the requirements of Table 2 are met, the batch represented by the identification test sample can be shipped according to the contract after obtaining the identification approval.
4.6 Screening
All gas sensors should undergo and pass all screening tests in the order and allowable non-conforming rate (PDA) listed in Table 3. Components that fail to meet the standards of any test should be removed from the batch when failure is found, or immediately removed from the batch as soon as the test in which failure is found is completed. These removed components cannot be shipped as products. Table 3 Screening
Internal visual inspection
Temperature cycling
Final test
Appearance and mechanical inspection
Method code
4.6.1 Permissible Defective Rate (PDA)
As specified
The electrical parameters used as the intermediate and final tests for 100% electrical aging in Table 3 shall be specified in the detailed specification and compared to determine whether the change (△) during aging indicates a batch stability problem. When specifying these electrical parameters, the number of components in the batch that fail to meet these parameters shall be specified. The number of components in the batch that fail to meet these parameters or the relevant () limit values shall not exceed 10%. If the PDA does not exceed 20%, it may be resubmitted for aging in accordance with the provisions of Article 4.6.3; if the PDA exceeds 20%, the batch shall not be accepted as a product. 4.6.2 Provisions for fatal failures in screening
In the screening test before electrical aging (excluding internal daily inspection), the failure of gas sensors in the batch due to internal short circuits, open circuits or instantaneous short circuits and open circuits shall be recorded in the test records. When the cumulative number of gas sensors with fatal failures exceeds 5%, the batch is considered to have failed the screening and shall not be submitted for quality consistency inspection. 4.6.3 Resubmitted batches for aging
Unless otherwise specified, a batch may be resubmitted for aging only if the electrical aging rejection rate does not exceed twice the specified PDA, and it may only be resubmitted for aging once. The resubmitted batch shall contain only the gas sensors from the original batch. The resubmitted batch shall be separated from the newly submitted batch and a tightened inspection with a PDA of 3% shall be used to verify all specified properties of the resubmitted aging batch. If the rejection rate of the resubmitted batch exceeds the tightened inspection PDA, the entire resubmitted batch shall not be accepted.
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