Abstract: A method of forming a coated titanium substrate comprises forming a titanium or titanium alloy based substrate, cleaning a surface of titanium substrate, coating an organic or inorganic solution on the surface of titanium substrate by plating, spraying, or rolling for forming a strong adhesion between titanium substrate and organic or inorganic solution, baking titanium substrate at a range from about 100° C. to about 230° C., and coating a layer of transparent paint on the surface of titanium substrate. This can form a strong adhesion between titanium substrate and transparent paint while demonstrating a unique surface property of titanium substrate.

Abstract: A guarding system of a credit card against unauthorized use includes one or more sets of letter-and-number series composed of letters and numbers stored in a credit card, and the same letter-and-number series as those of the credit card are set up in the data archives of the computer of a credit card issuing bank. The computer of the credit card issuing bank checks whether or not the letter-and-number series of the credit card coincide with those in its archives and deciding whether to allow the trading finished or not. Besides, the computer of the credit card issuing bank can automatically renew the letter-and-number series of the credit card every time after it is finished in trading. Then, these renewed data are checked and stored in the credit card and in the archives of the computer, surely preventing the credit card from copied and used by illegally and fraudulently.