Coated filters

A monolith is coated with an on-wall washcoat. This is coated with a powder coating comprising inorganic particles and silicone resin in a ratio 50:1 to 1:9 (3:1). The particles are preferably zeolite, especially CHA zeolite having d90 0.1-100 (6-10) µm. The mass loading of the powder coating is preferably 0.1-50 (5-25) g/l. The powder coating is sprayed as a dry particulate onto the wash-coat, preferably under a constant gas flow of 80-300 m3/hr. The coating is preferably calcined at 200-600 (400-530)°C, to give an inorganic particle to silicon dioxide ratio 65:1 to 1:7 (2:1) and pore size 1-100 (5-20) µm. The article is a filter, preferably a coated catalytic wall-flow filter for a vehicular exhaust gas system.