Test heating conditions:

14:20: The temperature of the hydrofluoric acid etching solution is 48 ℃; 14:40: the temperature of the hydrofluoric acid etching solution is 58 ℃; 15:00: the temperature of the hydrofluoric acid etching solution is 15 ℃; 15?:20: hydrofluoric acid etching solution temperature is 63 ℃.

Various manufacturers coating by hydrofluoric acid corrosion observed as follows:

XK-803:

1, Soaking 1.5 hours, the coating began to viscous material (fluoride), but no blistering phenomenon. 

2, Soaking 4 hours, the coating surface roughness, no blistering phenomenon. 

3, Soak 17 hours, the coating color, the coating of a large area of bubble, bubble-intensive, bubble point.

TH-3000F:

1, After several observations, no coating with color loss, blistering.

2, Soaking 3.5h, about 5 to 6 bubble point, sesame seeds large.

3, Soaking with hydrofluoric acid for 5 hours, the coating bubble point did not increase, no significantly become larger.

4, Soaking with hydrofluoric acid for 17 hours, the coating did not pale, the local coating with large bubbles.

XK-803:

1, Soak 1 hour, the coating began to sticky material (fluoride), but no blistering phenomenon. 

2, Soaking 4 hours, the coating surface roughness, no blistering phenomenon. 

3, Soaking 17 hours, the coating color loss, coating a large area of blistering, bubble-intensive.