With the continuous expansion of the working scope and application scenarios of semiconductor devices, it has provided strong support for the development of the information society. No matter from the perspective of science and technology or economic development, the importance of semiconductors is very great. Nowadays, semiconductors are mainly used in special environments such as high temperature, high power, high frequency and corrosion resistance. In such a special environment, a special environment that needs to withstand high and low temperatures and corrosion resistance needs to be tested to verify the reliability of this.

The compound salt spray test chamber is one of the most practical simulation experiments for semiconductors in the natural environment, which plays an extremely important role in checking the reliability and quality control of products.

01 Definition of composite salt spray test chamber

The composite salt spray test chamber can test the salt spray corrosion resistance of some products by examining the salt spray corrosion resistance of materials and their protective layers, as well as the process quality comparison of similar protective layers. The product is used for salt spray corrosion tests of parts, electronic components, protective layers of metal materials and industrial products. Simply put, it is to assess the corrosion resistance of the product.

Structure and Performance of Lijia Compound Salt Spray Bin

Real photograph of compound salt spray test chamber

The salt spray system is composed of salt water tank, pneumatic system, salt water storage tank, spray tower, nozzle, etc. The salt water flows from the outside to the laboratory by natural drop, and the salt solution is atomized by compressed air through the spray nozzle.

The temperature in the box is increased to the specified requirements by the bottom heater. After the temperature is stable, the spray switch is turned on, and the salt spray test is carried out at this time. Compared with the ordinary salt spray test machine, the temperature in the test room in this state is realized by heating the air by the heating rod. While ensuring the temperature uniformity, the influence of water vapor on the test results of the ordinary salt spray test machine is minimized.

The controller uses a true color touch screen, the program group 120 groups, the total number of cycles 1200 times.

Temperature sensor

Anti-corrosion platinum resistance PT100 Ω/MV

Heating mode

Adopt strong corrosion resistant high-speed heating electric heater, multi-point layout, stable and uniform

Spray system

Wall-mounted spray system, imported movable adjustable nozzle, long-term work without crystallization, uniform distribution of mist particles

Salt liquid collection

Conform to the national standard funnel and standard metering cylinder, settlement adjustable and controllable

Decompression

Two poles air intake decompression, to ensure the stability of the spray pressure.

02 Purpose of Experiment

Salt spray test is an environmental test that mainly uses artificial simulated salt spray environmental conditions created by salt spray test equipment to assess the corrosion resistance of products or metal materials.

It is divided into two categories, one is the natural environment exposure test, and the other is the artificial accelerated simulated salt spray environment test.

Artificial simulated salt spray environment test is to use a test equipment with a certain volume space-salt spray test box, and use artificial methods in its volume space to cause salt spray environment to assess the quality of salt spray corrosion resistance of products.

Compared with the natural environment, the salt concentration of chloride in the salt spray environment can be several times or dozens of times of the salt spray content in the general natural environment, which greatly improves the corrosion rate.

If a product sample is tested in a natural exposure environment, it may take 1 year to be corroded, but similar results can be obtained as long as 24 hours in an artificial simulated salt spray environment.

03 Common Standards

GB/T2423.17-2008 "basic environmental testing procedures for electric and electronic products test Ka: salt spray test method"

GB/T10125-2012 -2006/ISO 9227-2006 Brine spray test method

GB/T 2423.18-2012 environmental tests-Test methods-Test Kb: Salt spray, alternating (sodium chloride solution)

GB/T5170.8 Inspection Methods for Environmental Testing Equipment for Electric and Electronic Products-Salt Spray Test Equipment

GB/T10587-2009-Technical Conditions for Salt Spray Test Chamber

GB/T5170.11-2008 Test Methods for Corrosive Gas Testing Equipment

Environmental test methods for GJB150.11A-2009 military equipment. salt spray experiment

IEC60068-2-11, ASTMB117, JISH8502 and other relevant standards

02 Composite Salt Spray Test Chamber

The difference with ordinary salt fog box

General salt spray box is to complete NSS neutral salt spray test, ASS acetic acid salt spray test, CASS copper accelerated acetic acid salt spray test, and composite salt spray test box generally requires humidity control in the box, mainly to do salt spray damp heat alternating test, but also has the function of drying.

Ordinary salt spray test chamber can only carry out fixed value test, while composite salt spray test chamber can carry out cycle test.

Neutral salt spray test (NSS test): Neutral salt spray test is the earliest and most widely used accelerated corrosion test method. (Test temperature: 35 ℃)

Acetic acid salt spray test (ASS test):ASS test is developed on the basis of neutral salt spray test.

Copper salt accelerated acetic acid salt spray test (CASS test):CASS test is a rapid salt spray corrosion test recently developed abroad (test temperature: 50 ℃)

The test shows that

Cyclic corrosion is very close to outdoor corrosion relative to corrosion rate, structure and morphology, and has an excellent correlation with outdoor corrosion. It has long been included in the test category. More and more industry tests have to carry out multi-step cycles of salt spray, drying, humidity and heat.

China Saibao Semiconductor Lighting Product Testing Center-Lijia Compound Salt Spray Test Chamber (real shot of the operation of the test chamber)

03 The scope of application of the composite salt spray test cabin.

The compound salt spray test chamber is used for the natural condition closest to the actual in the accelerated corrosion test;

It is simulated by the conditions commonly encountered in the natural environment: for example, salt spray, hot air drying, humidity, low temperature, etc. are combined and can be cycled in any order. The main test items are aimed at items used in the environment with drastic changes, such as semiconductors, auto parts, aviation equipment, building materials, coating electric equipment, electrical machines, etc.

The composite salt spray test chamber can also test the performance of automobile parts in many aspects, truly restore the atmospheric salt spray corrosion environment, and is widely used in automobile testing work.

In the test process, it is necessary to select the test method in combination with the auto parts to achieve a multiplier effect. At the same time, attention should be paid to the introduction of advanced test equipment to make the test results more real and effective.