What are the common criteria for passing damp heat tests?

Date：2023-09-25 17:35:48Views：257

Damp heat test is a common environmental test used to evaluate the durability and stability of materials and equipment under high temperature and humidity conditions. In the damp heat test, the sample is exposed to a high-temperature and high humidity environment to simulate the high-temperature and high humidity environment that may be encountered in actual production and use, in order to evaluate the performance and reliability of materials and equipment. Common damp heat tests include constant temperature and humidity tests, cyclic damp heat tests, salt spray tests, etc.

So, what are the common criteria for passing damp heat tests? Let's take a closer look:

1. Qualification criteria for constant temperature and humidity test

The constant temperature and humidity test is a test that involves exposing a material to high temperature and humidity for a long time. Usually, the temperature for constant temperature and humidity testing is 85 ℃, the humidity is 85% RH, and the testing time is generally 1000 hours. In constant temperature and humidity tests, the performance and reliability of materials may change, so it is necessary to evaluate the test results. Common criteria for passing constant temperature and humidity tests include:

(1) Appearance: The surface of the sample should not show obvious discoloration, blistering, cracking, or other phenomena.

(2) Dimensional stability: The sample size should not undergo significant changes.

(3) Electrical performance: If the sample is an electronic component or electrical equipment, its electrical performance should meet the requirements.

2. Qualification criteria for cyclic damp heat test

The cyclic damp heat test is an experiment conducted alternately in an environment of high temperature, high humidity, and low temperature, low humidity. Usually, the temperature range of the cyclic damp heat test is -40 ℃ to 85 ℃, and the humidity range is 10% RH to 98% RH. The test time is generally 1000 hours. In the cyclic damp heat test, the performance and reliability of the material will also change, so it is necessary to evaluate the test results. Common qualification criteria for cyclic damp heat tests include:

(1) Appearance: The surface of the sample should not show obvious discoloration, blistering, cracking, or other phenomena.

(2) Dimensional stability: The sample size should not undergo significant changes.

(3) Electrical performance: If the sample is an electronic component or electrical equipment, its electrical performance should meet the requirements.

(4) Mechanical performance: If the sample is a mechanical component or equipment, its mechanical performance should meet the requirements.

3. Qualification criteria for salt spray test

Salt spray test is a corrosion test that simulates materials and equipment in marine environments. In the salt spray test, the surface of the sample is exposed to a salt spray containing a certain concentration to simulate corrosion in the marine environment. Typically, the test time for salt spray testing ranges from 24 hours to 1000 hours. Common criteria for passing salt spray tests include:

(1) Appearance: The surface of the sample should not show obvious corrosion, rust, or other phenomena.

(2) Dimensional stability: The sample size should not undergo significant changes.

(3) Electrical performance: If the sample is an electronic component or electrical equipment, its electrical performance should meet the requirements.

In summary, the common qualification criteria for damp heat tests mainly include appearance, dimensional stability, electrical performance, mechanical performance, and other aspects. When conducting damp heat tests, it is necessary to select appropriate test methods and conditions based on the characteristics of different materials and equipment, and make reasonable evaluations and judgments based on the test results.