Nickel is widely used as a bleaching element in white gold alloys, but it is a potential allergen. In this paper, a popular 18 KW gold alloy, often called ＂safe nickel,＂ was chosen as the experimental material; its ...Nickel is widely used as a bleaching element in white gold alloys, but it is a potential allergen. In this paper, a popular 18 KW gold alloy, often called ＂safe nickel,＂ was chosen as the experimental material; its nickel release rates under six different processing conditions were evaluated according to the EN1811 standard. The results reveal that both the surface processing method and heat treatment technology significantly affect the nickel release rate. A coarse surface releases more nickel ions than a smooth surface. The sample normalized at 700 ~C in the single region has a lower nickel release rate than the one treated at 550 ~C in the two-phase phase region, while high temperature normalizing at 800 ~C will accelerate it. All the measured nickel release rates of the experimental material under various processing conditions exceed the permitted threshold value in the Nickel Directive, which indicates that there exists the potential risk of nickel- induced allergy when it is used to make jewelries, espe- cially for piercing types.展开更多
Nickel-containing stainless steels have been widely applied in watch and jewelry production, and their re- sponses to the Nickel Directive become a universal concern in the industry. The nickel release rates and corro...Nickel-containing stainless steels have been widely applied in watch and jewelry production, and their re- sponses to the Nickel Directive become a universal concern in the industry. The nickel release rates and corrosion be- haviors of types 316L, 304, 303 and 201 stainless steels under the conditions of solid solution and mirror polishing were studied by artificial sweat soaking and electrochemical methods. The results show that the weekly nickel release rates in artificial sweat do not strictly correspond to the nickel contents, which present a descending order as 303 stainless steel of 2.06 μg/cm2 , 201 stainless steel of 1.51 μg/cm2 , 304 stainless steel of 0.08μg/cm2 and 316L stainless steel of 0.02 μg/cm2. Both the nickel release rates of type 303 and 201 stainless steels significantly exceed the threshold values regulated in EN1811 ： 2011 ; therefore, they should be avoided to be used as watch and jewelry materials owing to the risk of nickel sensitization. The nickel release rates of 316L and 304 stainless steels meet the requirements of the standard. Sulfide inclusions in stainless steel become the sources of pitting and exacerbate the damage of the passivation membrane, which is the significant cause to enhance the nickel release rates.展开更多
基金financially supported by the united foundation of the National Natural Science Foundation of China and Guangdong province (No. U1034002)
文摘Nickel is widely used as a bleaching element in white gold alloys, but it is a potential allergen. In this paper, a popular 18 KW gold alloy, often called ＂safe nickel,＂ was chosen as the experimental material; its nickel release rates under six different processing conditions were evaluated according to the EN1811 standard. The results reveal that both the surface processing method and heat treatment technology significantly affect the nickel release rate. A coarse surface releases more nickel ions than a smooth surface. The sample normalized at 700 ~C in the single region has a lower nickel release rate than the one treated at 550 ~C in the two-phase phase region, while high temperature normalizing at 800 ~C will accelerate it. All the measured nickel release rates of the experimental material under various processing conditions exceed the permitted threshold value in the Nickel Directive, which indicates that there exists the potential risk of nickel- induced allergy when it is used to make jewelries, espe- cially for piercing types.
基金financially supported by the foundation of Jewelry Engineering Technology Development Center of Guangdong Colleges and Universities(item No.131,Yue Edu.Sci)
文摘Nickel-containing stainless steels have been widely applied in watch and jewelry production, and their re- sponses to the Nickel Directive become a universal concern in the industry. The nickel release rates and corrosion be- haviors of types 316L, 304, 303 and 201 stainless steels under the conditions of solid solution and mirror polishing were studied by artificial sweat soaking and electrochemical methods. The results show that the weekly nickel release rates in artificial sweat do not strictly correspond to the nickel contents, which present a descending order as 303 stainless steel of 2.06 μg/cm2 , 201 stainless steel of 1.51 μg/cm2 , 304 stainless steel of 0.08μg/cm2 and 316L stainless steel of 0.02 μg/cm2. Both the nickel release rates of type 303 and 201 stainless steels significantly exceed the threshold values regulated in EN1811 ： 2011 ; therefore, they should be avoided to be used as watch and jewelry materials owing to the risk of nickel sensitization. The nickel release rates of 316L and 304 stainless steels meet the requirements of the standard. Sulfide inclusions in stainless steel become the sources of pitting and exacerbate the damage of the passivation membrane, which is the significant cause to enhance the nickel release rates.
