Direct-Write Thermal Sensors fabri-cated using thermal spray technol-ogy have several unique advan-tages over traditional sensors that have to be mechanically attached to engineering components. The unique microstructure and nanometer-scale features associat-ed with thermal spray coatings, including pores and cracks, voids, the presence of many splat-splat interfaces and micro cracks all result in unique thermal, mechani-cal, and electrical properties that result in excellent performance at very high temperatures (1000+ oC) and in harsh environments. These sensors can be fabricated directly onto engineering components for outstanding reliability. A key appli-cation for these sensors is their use in land-based turbines and high-temperature, high-pressure boilers for more efficient power genera-tion, condition-based (vs. failure-based) maintenance, and optimal performance. The work is funded by federal and industrial sources.