The Color Control On The Chemical Coloring Of Stainless Steel And The Study Of The P/Mo Heteropoly Acid Hardening Process

Since the last century seventy 's,the colored stainless steel has begun to put into the industrial production.After forty years of development,the coloring process is becoming more and more mature,but there are still some unresolved problems in the practical production.And the focus of the study are always the color reproducibility and the corrosion resistance of the colored stainless steel.This paper studies the color control method of the stainless steel and the different hardening liquid influence on the hardening effect of the colored stainless steel and the optimum hardening conditions,concrete work as follows:1.In the same condition,430stainess steel was colored by chemical coloring.The CS300 electrochemical workstation was used to control time consistency,potential consistency,potential difference consistency and the finish potential reach to stable.Each experiment has three samples.The reproducibility of the colored stainless steel's color was compared.The results show that:(1)the color reproducibility of the stainless steel's chemical coloring doesn't fully comply with the internationally recognized principle:when the potential difference reach the same,the thickness of the coloring film will reach the same,so the color of the colored stainless steel also will reach the same;(2)when reaching the coloring time consistent,coloring potential consistent and coloring potential difference consistent,the colored stainless steel 's color reproducibility are difficult to achieve;(3)the effect on controlling the coloring time and the coloring potential consistent are worse than controlling the potential difference consistent;(4)when the colored stainless steel reached the finish potential for a period of time,the color can reach agreement.2.The colored stainless steel(green)as the cathode and the tinplate as the anode were respectively arranged in the sulfuric acid/chromic anhydride,phosphate/chromic anhydride and phosphorus molybdenum heteropoly acid/chromic anhydride for electrolytic hardening.The experiment of EDX showed that the sulfur element,the phosphorus element and the molybdenum element were deposited on the surface of the colored stainless steel.The polarization curves and SEM experiment showed that the corrosion resistance of the colored stainless steel through electrolytic hardening was better than the colored stainless steel which not be hardening;the different hardening liquid effect on the corrosion resistance of the colored stainless steel was not same;the colored stainless steel hardening by phosphorus molybdenum heteropoly acid and chromic anhydride owned smooth and densification oxidation film and best corrosion resistance.3.Choosing the best hardening liquid ratio:P/Mo(12:1):2.5g/l,CrO3:250g/l to electrolytic hardening conditions orthogonal experiment on 430 colored stainless steel plate.The reaction time,the reaction temperature and the current density were chosen as the different factors,each factor has five levels.The orthogonal experiment was designed for three factors and five levels.When we were computing the the results of the experiment,we need to respectively calculated the pitting potential of the K value,the corrosion current of the K value and the release efficiency of the K value.The results showed that the optimum reaction conditions of the electrolytic hardening was 50??15min and 5mA/cm2.