The adhesion of the coating film directly affects the service life of the workpiece. Many manufacturers have strict requirements on the film layer when coating workpieces, so when purchasing vacuum coating machines, the selection of coating technology is also more cautious. Let's introduce the research process of film adhesion to you in the following vacuum series, hoping to help you.

When magnetron sputtering coating is carried out on polymer coating, the film is very thin, usually 50 ~ 200 nm, so the test of adhesion of ultra-thin coating on this soft substrate is different from the test of adhesion of coating in the usual sense. For the ordinary adhesion test of polymer coating, because its thickness is usually several to several tens of microns, it is generally possible to directly peel off the coating or other standard methods to test the adhesion. For metal coating on hard substrate, more than 20 methods have been proposed, including stretching method, shearing method, pulling down method, grinding method, etc. There is almost no connection between different methods, and the data difference can reach two orders of magnitude, so the data obtained by various methods cannot be used universally. At present, there are few reports on the adhesion test of ultra-thin coatings on polymer coated substrates in China. In this study, the adhesion of ultra-thin coating was tested by aluminum column adhesion method.

Test method of coating film of magnetron sputtering vacuum coater: (1) Test method of coating adhesion After the coated aluminum column is adhered by adhesive, the thread at the other end of the aluminum column is connected with the tensile chuck of the material tensile tester, and the adhesion is investigated in two cases by testing the tensile strength of the adhered aluminum column. When no coating falls off on the failure surface, the adhesion of the coating is greater than the tensile strength of the bonded aluminum column. When the coating falls off on the failure surface, the tensile strength of the aluminum column is approximately the adhesion of the coating.

Test process of coating film in magnetron sputtering vacuum coating machine;

(1) aluminum column coating pretreatment: use 400# and 600# water mill sandpaper to polish the adhesive surface of aluminum column, rinse it with tap water, and dry it in an oven at (80±5)℃ for 1h. After diluting 100 parts of polyurethane coating with 30 ~ 50 parts of industrial butyl acetate, brush it on the opposite side (only one of two opposite aluminum columns is brushed), then put the brush side up, heat it in an oven at (60±5)℃ for 1h, and then raise the temperature to (80±5)℃ and keep the temperature for 5 ~ 6h。

(2) Coating the aluminum column The brush coating surface of the aluminum column is subjected to magnetron sputtering coating treatment, and the treatment process parameters are as follows:

Coating material                   H62

Sputtering power/kw             20 ~ 30

Sputtering time /min              2

Sputtering pressure/pa          0.1 ~ 0.4

Target base distance /mm     600

(3) Butt-bonding of aluminum column: Glue the coated aluminum column immediately. Three kinds of adhesives are used: unsaturated polyester putty, one-component polyurethane varnish and epoxy resin adhesive, and then use another new aluminum column to butt-bond with it. After compaction, it was cured at room temperature for 24h, then heated at (70±5)℃ for 6h, and then the tensile strength of aluminum column was tested.