Electrochemical corrosion potential sensor and method of making

A sensor for measuring electrochemical corrosion potential comprising:

• a tubular ceramic probe comprising zirconia and having a closed tip at one end, said probe at least partially filled with a powder comprising iron and iron oxide;
• a metal support tube having one end receiving an opposite end of said probe, and joined thereto by a braze joint therewith;
• an electrical conductor extending through said support tube and into said probe, and having an end buried in said powder for electrical contact therewith;
• and
• a protective band bridging said probe and tube at said joint for sealing thereof, said protective band consisting essentially of a metallic coating, said coating comprising at least one metal selected from the group consisting of a tantalum alloy, a zirconium alloy, a nickel alloy, a stainless steel, and a titanium alloy, wherein said band locally coats said probe and said tube at said braze joint, such that said probe tip is uncoated by said band.

A method for manufacturing a sensor for measuring electrochemical corrosion potential, said method comprising:

• providing a tubular ceramic probe having a closed tip at one end, said probe at least partially filled with a powder comprising metal and metal oxide;
• providing a metal support tube having one end receiving an opposite end of said probe;
• joining said tube with said probe by forming a braze joint therewith;
• and
• depositing a protective band bridging said probe and said tube at said joint for sealing thereof, said protective band consisting essentially of a metallic coating.

A method for manufacturing a sensor for measuring electrochemical corrosion potential, said method comprising:

• providing a tubular ceramic probe comprising zirconia and having a closed tip at one end, said probe at least partially filled with a powder comprising metal and metal oxide;
• providing a metal support tube having one end receiving an opposite end of said probe;
• joining said tube with said probe by forming a braze joint therewith;
• and
• depositing a protective band bridging said probe and said tube at said joint for sealing thereof, said protective band consisting essentially of a metallic coating, wherein depositing said protective band comprises applying said coating by a process selected from the group consisting of plasma spraying, high-velocity oxy-fuel (HVOF) spraying, chemical vapor deposition, physical vapor deposition, electroless plating, electrophoretic deposition, and electroplating, said metallic coating comprising at least one metal selected from the group consisting of a tantalum alloy, a zirconium alloy, a nickel alloy, a stainless steel, and a titanium alloy,
• wherein depositing said protective band further comprises locally applying said coating to said probe and said tube at said braze joint such that said probe tip is uncoated by said band.