Safety issues on food-contact stainless steels

The investigation on toxicity of stainless steel has been reviewed. Many countries have established laws to guarantee food safety of stainless steel containers. The development of food safety standards with respect to the use of stainless steels in China has been analyzed. Influence of stainless steel grades and food ingredients on the release of metal ions has been reviewed briefly. The effect of surface condition on the release of metal ions has also been analyzed. Finally, the food safety issues with respect to the use of stainless steel products have been presented systematically.

The “Thirteenth Five Year” Development Plan for Nonferrous Metals Industry was Formally Released

On October 18,the Ministry of Industry and Information Technology compiled and promulgated'Development Plan for Nonferrous Metals Industry(2016-2020)'i.e.the'Thirteenth Five Year'Development Plan for Nonferrous Metals Industry(MIIT G[2016]No.316,hereinafter The'Plan').The'Plan'mentioned that,by the end of 2020 China’s nonferrous metals industry will join the ranks of world powers.

Influence of Fluoride Content of Artificial Saliva on Metal Release from 17-4 PH Stainless Steel Foam for Dental Implant Applications

Highly porous 17-4 PH stainless steel foam for implant applications was produced by space holder technique. Metal release and weight loss from 17-4 PH stainless steel foams were investigated in fluoride added artificial saliva environment by static immersion test. An inductively coupled plasma-mass spectrometer was employed to measure the concentrations of various metal ions. Effects of fluoride content of artificial saliva on metal release and weight loss from the steel foams were investigated. Effects of immersion time, pH value and process parameters on the weight loss and metal release were determined. Pore morphology, pore size and mechanical properties of the 17-4 PH stainless steel foams were also characterized.

Metal release/accumulation during the decomposition of Potamogeton crispus in a shallow macrophytic lake

Changes in metal concentrations in the litter of Potamogeton crispus were monitored during a consecutive 40-day in situ decomposition experiment using the litterbag method.The accumulation index was calculated and used to indicate the changes in the metals in litter.The results showed that the concentrations of Al,Cd,Cr,Fe,Mn,and Pb in litter increased significantly during the decomposition,while Cu and Zn concentrations decreased dramatically.Significant positive correlations were found between the concentrations of Al,Cr,Fe,and Mn and between Cu and Zn.Moreover,Cu and Zn both negatively correlated with Al and Fe.The remaining dry mass was negatively correlated with Al and Fe concentrations but positively correlated with Cu and Zn concentrations.Generally the accumulation index values of metals other than Al were less than one,indicating that the litter of P.crispus acted as a source of metals to the surrounding water body.Al was the only metal that showed continuous net accumulation in litter.The net accumulation of Fe and Mn in litter during the last 10 days of the experiment may indicate the precipitation of Feand Mn-oxides.It was estimated that 160 g/m^2（dry weight）P.crispus was decomposed in40 days.This was equivalent to releasing the following amounts of metals：0.01 mg Cd,0.03 mg Cr,0.71 mg Cu,0.55 mg Mn,0.02 mg Pb and 13.8 mg Zn into surrounding water,and accumulating 149 mg Al and 11 mg Fe,in a 1 m^2 area.

Fretting-corrosion mechanisms of Ti6Al4V against CoCrMo in simulated body fluid under various fretting states

Ti6Al4V alloy‒CoCrMo alloy pair is commonly applied for modular head‒neck interfaces for artificial hip joint.Unfortunately,the fretting corrosion damage at this interface seriously restricts its lifespan.This work studied the fretting corrosion of Ti6Al4V‒CoCrMo pair in calf serum solution.We established this material pair’s running condition fretting map(RCFM)regarding load and displacement,and revealed the damage mechanism of this material pair in various fretting regimes,namely partial slip regime(PSR),mixed fretting regime(MFR),and gross slip regime(GSR).The damage mechanism of Ti6Al4V alloy was mainly abrasive wear induced by CoCrMo alloy and tribocorrosion.Adhesive wear(material transfer)also existed in MFR.The damage mechanism of CoCrMo alloy was mainly abrasive wear induced by metal oxides and tribocorrosion in GSR and MFR,while no apparent damage in PSR.Furthermore,a dense composite material layer with high hardness was formed in the middle contacting area in GSR,which reduced the corrosion and wear of Ti alloys and exacerbated damage to Co alloys.Finally,the ion concentration maps for Ti and Co ions were constructed,which displayed the transition in the amount of released Ti and Co ions under different displacements and loads.