Automotive Electronics Humidity Chamber - GM 9537P Humidity Testing

    Temperature and Humidity Test Chamber is used to test the performance of materials in various environments and test the heat resistance, cold resistance, dry resistance and humidity resistance of various materials. Suitable for testing the quality of products such as electronics, electrical appliances, mobile phones, communications, meters, vehicles, plastic products, metals,food, chemicals, building materials, medical care, aerospace, etc.

TEST CHAMBER APPLICATIONS
1. To simulate test environment with different temperature and humidity
2. Cyclic test includes climatic conditions: holding test, cooling-off test, heating-up test, moistening test and drying test…
3. Cable port with flexible silicone plug for cable routing to provide the condition of test unit under operation
4. Uncover test unit weakness in a short-term test with accelerated time effect

The following problems are common with electronic components in hot and humid environments:

Physical phenomena:

Adsorption: gas molecules (water vapor molecules) in the space movement collision of solid material (test product) surface, when a certain number of gas molecules “stay” on the surface of the test product concentration is higher than its concentration in the gas phase, will produce condensation, this phenomenon is called adsorption.

Condensation: a phenomenon in which water molecules are adsorbed on the test product, but is generated when the test temperature changes. In the warming phase, the surface temperature of the test product is lower than the dew point temperature of the surrounding air, water vapor will condense into liquid on the surface of the test product to form water droplets. In the alternating heat and humidity test of the warming phase, due to the thermal inertia of the subject product, so that its temperature rise lagged behind the temperature of the test chamber, the surface will produce condensation phenomenon. In the cooling phase of the alternating heat and humidity test, the inner wall of the closed shell than the air inside the shell cools down faster, there will also be condensation.

Diffusion: water vapor is drawn into the inside of the device with the help of temperature by diffusion, thermal movement, respiration and capillary phenomenon.

Absorption: The amount of water vapor inhalation is related to temperature, absolute humidity and time. The higher the temperature, the greater the activity energy of water molecules, and the easier it is for water molecules to enter the inside of the device. The greater the absolute humidity, the greater the water molecule content, the possibility of water molecules penetrate into the interior of the device also increases.

Respiration: the inhalation of water vapor is also related to respiration.

Frequently Asked Questions:

Outer lead corrosion: In hot and humid environments, the action of water vapor, elemental chlorine, etc. can cause corrosion of aluminum, resulting in outer lead corrosion.

Shell corrosion: The plating of the tube shell may flake off and the outer leads may rust or rust off.

Ion Migration: Water vapor entering the inside of the device may cause ion migration, leading to short circuit or leakage inside the device.

Encapsulation Material Problems: Encapsulation materials may have problems with insulation, expansion and mechanical properties. Such as insulation performance degradation, material expansion, mechanical strength reduction.

Insulation degradation: when the humidity is too high, electronic components are susceptible to moisture, causing short circuits or insulation degradation and other failures; high humidity is also easy to produce condensation inside the precision electronic and mechanical equipment and the working surface, affecting the performance of the components inside the device and the stability of the work.

Metal corrosion: when the humidity exceeds a certain threshold, it will accelerate the corrosion of metal, resulting in rust or damage to components.

Static electricity problem: when the humidity is too low, it will produce more static electricity, which will also bring adverse effects on electronic products.

Changes in electrical parameters: For semiconductor devices, if water vapor penetrates into the core, it will also cause changes in electrical parameters.

Problems with moving parts: In hot and humid environments, materials absorb moisture faster, and even produce adsorption, diffusion and absorption phenomena and respiration, so that the surface of the material is swollen, deformed, blistered, coarsened, and will also increase friction or even jamming of moving parts.

Chip welding failure: chip and solder are different materials with different coefficients of thermal expansion, so there is a thermal mismatch at high temperatures. In addition, the existence of welding voids will increase the thermal resistance of the device, so that the heat dissipation becomes worse, the formation of hot spots in the local area, causing electromigration and other temperature-related failures occur.

Internal lead bonding failure: mainly corrosion failure at the bonding point, temperature cycling or vibration leading to fatigue fracture of the aluminum bonding leads.

Aluminum-related interfacial effects: In silicon based electronic devices, the SiO2 layer and aluminum will react chemically at high temperatures, thinning the aluminum layer. Gold lead wires and aluminum interconnect wires or aluminum bonding wire and shell gold-plated lead bonding, will produce Au-Al interface contact, after long-term use or high temperature storage of more than 200 ℃ will produce a variety of intermetallic compounds, and because of their lattice constants and thermal expansion coefficients of the different, in the bonding point of a great deal of stress within the conductivity becomes smaller.

Metallization corrosion: Aluminum connecting wires on the chip are susceptible to corrosion by water vapor in hot and humid environments.

Capacitor problems:

Short circuit: Flying arc between the edge of the poles at high temperature and low air pressure will lead to short circuit of the capacitor, in addition to the external impact and other mechanical stresses will also cause dielectric transient short circuit.

Open circuit: Oxidization of the lead wires and electrode contacts due to humid and hot environments, resulting in low-level inaccessibility as well as corrosion and fracture of the anode lead foil.