Method of manufacturing liquid jet head, a method of manufacturing a piezoelectric element and a liquid jet apparatus

A liquid jet head manufacturing method comprising:

• preparing a first board which is provided with pressure generating chambers individually communicating with nozzle openings for ejecting a liquid;
• and
• forming a piezoelectric element which includes a first electrode film formed on an area opposed to each of the pressure generating chambers of the first board, a piezoelectric layer, and a second electrode film formed on a surface of the piezoelectric layer opposite to the first electrode,
• wherein the step of forming the piezoelectric element includes forming a first electrode metal layer containing iridium on the first board, forming the piezoelectric layer having a plurality of piezoelectric films by performing a step of forming a piezoelectric precursor film on the first electrode metal layer and subjecting the piezoelectric precursor film to heat treatment to form the piezoelectric film plural times, and forming the second electrode film on the piezoelectric layer, and
• wherein the step of forming the first electrode metal layer includes forming the first electrode metal layer so as to contain one or more iridium layer and permit the iridium layer to have the total thickness in the range from 2 to 5 nm and forming the first electrode film by performing heating at a temperature in the range from 400 to 650° C. for 30 minutes or more after a first piezoelectric film is formed in the step of forming the piezoelectric layer to oxidize the iridium contained in the first electrode metal layer.