An improved chemical vapor deposition apparatus and procedure is disclosed. The technique provides improved shielding of the reaction and deposition zones involved in providing CVD coatings, whereby coatings can be produced, at atmospheric pressure, of materials which are sensitive to components in the atmosphere on substrates which are sensitive to high temperatures and which are too large, or inconvenient, to process in vacuum or similar chambers. The improved technique can be used with various energy sources and is particularly compatible with Combustion Chemical Vapor Deposition (CCVD) techniques.