Niobium sputtering targets
Purity :  2N, 2N7,3N, 3N5 or best purity with 99.95%              
Chemical composition required:
             Fe        20 ppm max.
             Ni         25ppm max.
             Cr        5 ppm max.
             Cu        5 ppm max.
             Zr         50 ppm max.
             P          30 ppm max.
             Si         30 ppm max.
             Ta        400 ppm max.
             W         50 ppm max.
             Mo        50 ppm max.
             Na        3 ppm max.
             Li          5 ppm max.
             K          3 ppm max.
             U          0.1 ppm max.
             Th        0.1 ppm max.
             Others  10 ppm max.
             C          40 ppm max.
             O          150 ppm max.
             N          100 ppm max.
             H          15 ppm max.
Surface finish: Ra 0.4 ( RMS64 or better)
Flatness  : 0.1mm
Grain size: 60 micron or ASTM 4 or better.
Tolerance: +/-0.010" on all dimensions
Size available : 
Niobium target (round target) :
1" up to 15" diamter x 0.2362" to 0.25" thickness;
Niobium target (rectangular target and square target):
0.125" to 0.5000" thickness x 4.92" up to 25.59" width x 40" Length.
Typical size :
Round Niobium target :
Tolerance     : +/-0.010" on all dimensions
50.8mm diameter x 3.175mm thickness  ( 2" dia X .125"  thk), purity 3N8
50.8mm diameter x 6.35mm thickness    ( 2" dia X .250"  thk), purity 3N8
101.6mm diameter x 3.175mm thickness( 4" dia X .125"  thk), purity 3N8
101.6mm diameter x 6.35mm thickness  ( 4" dia X .250"  thk), purity 3N8
127mm    diameter x 3.175mm thickness( 5" dia X .125"  thk), purity 3N8
127mm    diameter x 6.35mm thickness  ( 5" dia X .250"  thk), purity 3N8
152.4mm diameter x 3.175mm thickness( 6" dia X .125"  thk), purity 3N8
152.4mm diameter x 6.35mm thickness  ( 6" dia X .25"  thk),   purity 3N8
262mm    diameter x 12.7mm thickness   (10.31" dia X .50"  thk), purity 3N5
6.00mm Thickness x 203.20mm Diameter;
6.35mm Thickness x 381mm Diameter;

Rectangular Niobium target :
5.08mm x 124.97mm x 698.50 (0.20" Thickness x 4.92" Width x 27.50" Length);
6.35mm x 177.80mm x 635mm (0.25" Thickness x 7.0" Width x 25" Length);
6.00mm Thickness x 138mm Width x 300mm Length;
6.35mm Thickness x 200mm Width x 650mm Length;
We can tailor the sizes upon request.

Standard Specification ASTM B 393 -05 for Niobium Ribbon, Niobium Alloy Ribbon, Niobium Strip, Niobium Alloy Strip, Niobium Foil, Niobium Alloy Foil, Niobium Sheet, Niobium Alloy Sheet, Niobium Plate, Niobium Alloy Plate.
This specification covers five grades of wrought Niobium Ribbon, Niobium Alloy Ribbon, Niobium Strip, Niobium Alloy Strip, Niobium Foil, Niobium Alloy Foil, Niobium Sheet, Niobium Alloy Sheet, Niobium Plate, Niobium Alloy Plate. as follows: (Committee B10 has adopted "niobium" as the designation for Element No. 41, formerly named "columbium".)
1. ASTM B 393 -05 UNS R04200 -Type 1, Reactor grade unalloyed niobium;
2. ASTM B 393 -05 UNS R04210 -Type 2, Commercial grade unalloyed niobium;
3. ASTM B 393 -05 UNS R04251 -Type 3, Reactor grade niobium alloy containing 1% zirconium;
4. ASTM B 393 -05 UNS R04261 -Type 4, Commercial grade niobium alloy containing 1% zirconium;
5. ASTM B 393 -05 UNS R0xxxx  -Type 5, Residual Resistivity Ratio(RRR) grade pure niobium.
RRR values :  guaranteed min. RRR 300 *,    
* the Residual Resistivity Ratio RRR is defined as the ratio of electrical resistivity at 295K to electrical resistivity at 4,2K.