US 12,030,787 B2
Process for synthesizing rare earth-doped cobalt-chromite pigments for capacitive and resistive humidity sensor applications
Mohd. Shkir, Abha (SA); Thamraa Alshahrani, Riyadh (SA); Anuj Kumar, Mathura (IN); S. AlFaify, Abha (SA); Mohd Ubaidullah, Riyadh (SA); N. Senthilkumar, Clement Town Dehradun (IN); and Jagadeesha Angadi. V, Hubballi (IN)
Assigned to Mohd. Shkir, Abha (SA); and Princess Nourah bint Abdurahman University, Riyadh (SA)
Filed by Princess Nourah bint Abdurahman University, Riyadh (IN); and Mohd. Shkir, Abha (SA)
Filed on Apr. 28, 2023, as Appl. No. 18/309,371.
Prior Publication US 2023/0357047 A1, Nov. 9, 2023
Int. Cl. C01G 51/00 (2006.01); G01N 27/12 (2006.01); G01N 27/22 (2006.01); H01B 1/08 (2006.01)
CPC C01G 51/40 (2013.01) [G01N 27/121 (2013.01); G01N 27/223 (2013.01); H01B 1/08 (2013.01); C01P 2002/54 (2013.01); C01P 2002/72 (2013.01); C01P 2004/02 (2013.01); C01P 2004/32 (2013.01); C01P 2006/16 (2013.01); C01P 2006/40 (2013.01); C01P 2006/60 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A process for synthesizing rare earth-doped cobalt-chromite pigments for capacitive and resistive humidity sensor applications, the process comprises:
crushing metal nitrates and rare earth material (R) using a hydraulic press to form a powder of both metal nitrates and rare earth nitrates;
dissolving the powder of metal nitrates and rare earth material (R) with fuels in 30 milliliters of distilled water with constant stirring using a magnetic stirrer to form a green color solution;
heating the green color solution at 425 degrees Celsius for half an hour to obtain a green powder;
extracting and grinding the green powder in an agate mortar for 1 hour to form a fine green pigment; and
annealing the fine green pigment in a muffle furnace for two hours at a temperature of 500-600 degrees to remove organic residue and obtain rare earth-doped cobalt-chromite pigments.