Nickel oxide is a chemical that is commonly used in electroplating, frit manufacturing, and ferrite magnets. It is often available in different particle sizes and forms. NiO powder can be produced in high purity.

A new study investigated the release of nickel from NiO and nickel metal powders. Comparing results, the authors found that the relative release of Ni from these powders was dependent on particle size, surface area, and manufacturing process. The relative amount of nickel released was also higher for the powder than for the metal.

The toxicity of the material was studied by administering the powders to rats. Twenty percent of the rats given nickel powder in addition to manganese showed tumor formation. This was in contrast to the case of the metal powder, which protected against the induction of tumors.

Results suggest that the relative amount of nickel released from a nickel metal powder was approximately six times greater than that from an oxide powder. Release rates increased with time, suggesting that the powder particles were becoming more active with time.

The highest rate of release was observed after 6 hours of exposure. This was in accordance with previous literature findings. However, larger variations in nickel release were observed based on the particle size, the agglomeration, and the concentration of the powder.

The nickel oxidation half-life was shorter in the tracheobronchiolar compartment. For a 4.0 um NiO particle, the biological half-life was 21 mo. Enhanced nickel release was seen in solutions with reduced pH.

tags: semiconductor semiconductor material