Brief introduction of tape-cast wireless charging zirconia ceramic backplane technology

The zirconia ceramic mobile phone backplane has been adopted by Apple, Xiaomi and other communication devices. It not only has a beautiful appearance, but also can be charged wirelessly. The following Kezhong Ceramics Factory will introduce the technical process of casting a wireless charging zirconia ceramic backplane.

Process example of tape-cast wireless charging ceramic backplane

1. Preparation of ceramic body:

Take 10Kg zirconia powder and 2-3Kg glass powder (the glass powder can be composed of SiO2, Al2O3, B2O3, Na2CO3, CaCO3), use zirconium balls as the grinding medium, and methyl ethyl ketone as the solvent. The materials: balls: solvent (mass percentage )=1: (1.5-2): (0.5-0.8), ball milling for 20-22h, adding polyvinyl butyral (PVB) as binder, dimethyl phthalate as plasticizer, glycerin Base oleic acid is used as a dispersant, ball milled for 2-3 hours, vacuum defoamed and filtered, and tape-cast to make a membrane with a thickness of 0.5-0.6mm, that is, a ceramic body.

2. Preparation of conductive paste:

Take 8-15g of gold powder, 40-60g of nickel powder, 20-30g of tungsten powder, and 8-15g of borosilicate glass powder, and add organic solvents such as terpineol and methyl cellulose accounting for 15-30% of the weight of the solid powder in the nanometer Sand mill in a sand mill for 20-22 hours, and mix the above raw materials evenly to make a conductive paste.

3. Screen printing:

The conductive paste prepared in the above steps is printed on the ceramic body by screen printing, with a thickness of 15-20μm. 20-30min.

4. Lamination and isostatic pressing:

After the drying is completed, the same ceramic body as in step 1 is punched, and the wiring position is reserved, and the contact point of the conductive coil is covered on the surface of the ceramic body with the conductive paste, and isostatically pressed. The two are compressed, and 3D structures can be formed in addition to the flat shape.

5. Sintering:

The ceramics that have passed the above steps are sintered in a high-temperature reducing atmosphere furnace such as nitrogen or hydrogen sintering furnace. The sintering temperature is 1200-1300°C, so that the conductive paste adheres to the zirconia ceramics, and the two ceramic green bodies are sintered. After combining.

6. Post-processing and testing:

The sintered ceramic green body is processed, ground, and polished to make a ceramic mobile phone back plate with wireless charging function. Each wireless charging ceramic mobile phone back plate prepared by the above method is tested and inspected on the test equipment for charging efficiency.

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