8.7.5.8 Claims to Alloys

Date Published

In Mond Nickel Co. Ltd.'s Application (1948) 65 RPC 123, the invention was a new alloy. Alloys are a well investigated art in which slight changes of constituents or of relative proportions are often known to change the entire character of the resultant alloys. An imprecise claim which was not limited to the actual alloys disclosed in the specification was held to be not allowable on the grounds that it not only claimed the alloys disclosed in the specification, but was drafted sufficiently broadly to include hypothetical equivalent alloys which had not been investigated at all, and, in view of the state of the art, were not part of the invention.

Very small differences in the composition of an alloy can make a large difference in physical properties.  Such differences cannot be predicted and hence the invention will reside in specific alloy compositions which have particular desired properties. In these cases, imprecise terms such as “about” or “including”, or including the presence of some undefined alloy components or claiming component amounts outside the described ranges, are not limited to the inventive alloys described.  The claims therefore travel beyond the subject matter of the invention and are not fairly based.  Note, however, that including a statement in the claim identifying the presence of unavoidable impurities within the alloy is allowed.