Importance of Alumina Ceramics Purification
During the manufacturing process, electric vacuum ceramics are vulnerable to contamination by dust and other contaminants. Ceramic parts that are contaminated will result in serious impacts, such as a reduction in their dielectric strength, a massive increase in their deflated volume, and a decrease in their adherence to the metallized layer. Electric vacuum ceramics require repeated purification during the application process to eliminate functional faults in the devices they are used in. The most prevalent electric vacuum ceramics are alumina-based. Therefore, this study describes a simple, easy-to-implement, easy-to-operate purification method for alumina ceramics. The process is as follows.
Remove Adhesive Substances on the Surface of Alumina Ceramics
In the first place, fill a container with xylene or toluene and set the alumina ceramic that has to be cleaned in it. After that, place the alumina ceramic, xylene, and toluene in a kettle or beaker made of enamel, and bring the mixture to a boil for around an hour and a half. This will ensure that any and all contaminants are completely removed. The xylene and toluene should then be dumped out of the container, and the alumina ceramics should be washed in hot water. The amount of time needed to wash is between 20 and 30 minutes. Finally, put the alumina ceramics into the drying box and heat it to between 60 and 80 degrees Celsius for ten to fifteen minutes.
Degreasing of Alumina Ceramics
Measure out the amounts of sodium oxalate, sodium tartrate, OP emulsifier, and deionized water using a scale. To make a solution for pickling, use a pickling jar to combine the measured amounts of sodium oxalate and sodium tartrate with deionized water. Degreasing solutions are often made by reintroducing OP emulsifier after heating the solution to about 40 and 45 degrees Celsius. The following is a breakdown of the weight of each component of the degreasing solution: three parts sodium oxalate, two parts sodium tartrate, one and a half parts OP emulsifier, and one thousand parts deionized water.
The next step is to place the alumina ceramic into the degreasing solution, soak it for 15 to 20 minutes, and wipe it with a brush after it has been soaked and degreased. Finally, place the alumina ceramic into an ultrasonic cleaning tank with a heater. It is recommended that an ultrasonic treatment be carried out, with the ultrasonic treatment time lasting no less than 15 minutes and the ultrasonic vibration frequency not exceeding 20 KHz. Finally, rinse the components with hot water for 15 to 20 minutes, followed by a cold water rinse for 5 to 10 minutes.
Pickling of Alumina Ceramics
Weigh a particular volume of 30% hydrogen peroxide, 25% ammonia water, and formic acid. Put the alumina ceramics into the pickling container, and pour 30% hydrogen peroxide and 25% ammonia water, which occupy one third of the volume of the container, into the acid washing container to completely immerse the alumina ceramics. Then pour formic acid in a fine stream to pickle the alumina ceramics. The pickling time is 8-10 minutes.
Afterwards, the alumina ceramic should be rinsed for 3-5 minutes with cold water, followed by 3-5 minutes with deionized water. The alumina ceramic is then placed in an ultrasonic tank for ultrasonic treatment—the ultrasonic vibration frequency is 20 KHz, and the resistance of the water at the ultrasonic tank's outlet must be stronger than 5ΜΩ. Rinsing the alumina ceramics with deionized water for fifteen minutes while sonicating them produced the best results. Last but not least, the alumina ceramics are dried in the drying oven, where the temperature of the drying oven is 230 +/- 20 degrees Celsius, and the time is 60 +/- 5 minutes.
At last, checking the alumina ceramics.If there is still dirt on the surface, repeat the above steps.