few microns to hundreds of microns as would be envisaged by those skilled in the art the invention also includes the situation where the metallic zinc includes a coating of carbonate which often forms on metallic zinc upon exposure to moist air alternatively the source of zinc may be a zinc compound capable of being converted into zinc ion examples of zinc compounds that may be used in the present invention include zinc chloride and zinc hydroxide the essential feature of the processing gas es is that at least one oxidising gas is present such gases include oxygen and essentially any gas containing an oxygen atom e g no x as long as its recombination potential is higher than the formation of zno as this gas will be dissociated and ionized under the source oxygen is the preferred oxidising gas and the oxygen content preferably ranges from lt 10 to gt 90 by weight other gases in the mixture can include the assistive gases such as ar n 2 and h 2 in one case as an illustrative example the gas mixture is air and u02dc 18 by weight of ar with trace of water vapor from the humid air apparatus used to facilitate the process of the invention will require a high temperature heat source which includes but is not limited to gas fuel combustion plasma hotbox electrical arc etc so long as evaporation of metallic zinc is possible one preferred arrangement uses plasma torches as the heat source in this.