Knowledge

It is found that the thiocyanate anions (SCN-) strongly adsorb on the titanium surface in 30% sodium thiocyanate (NaSCN) at 80°C to form a protective barrier. Cl- ions compete with SCN- for adsorp

Titanium shows distinctive electrochemical noise in 3% NaCl at 80 °C before pitting. Metastable pits generate brief, low amplitude current spikes of 0.1-1 µA, lasting 0.1-1 second. Stable pi

With heating of the solution, bicarbonate crystals precipitate. This is a slurry of 20% sodium bicarbonate (NaHCO3) at 60 C. The Mohs hardness of these crystals is 2.5–3.0, which is somewhat low

Calcium ions precipitate as calcium phosphate (Ca₃(PO₄)₂) scale in 5% sodium tripolyphosphate (STPP) at 90°C. This scale is characterized by a low thermal conductivity of 0.3–0.6 W/m·

The ratio of HNO₃ to HF in the mixture of hydrofluoric (HF) and nitric (HNO₃) acids controls the corrosion morphology. At a low ratio of 2:1 (e.g. 0.5% HF + 1% HNO3) pitting dominates due to incomplet

In solutions of sodium metasilicate (Na₂SiO₃) at 80°C, silicate ions polymerize on titanium surfaces. At pH values above 11, a continuous, non-porous, protective film of 0.5–2 µm thick

PFA (perfluoroalkoxy) sheath heaters have to be designed for 70 % sulfuric acid at 160°C and 2 bar pressure so that the temperature at the interface to the resistance wire stays below the continuo

After exposure to 98% sulfuric acid at 180°C for 500 hours, PFA (perfluoroalkoxy) forms a white, crystalline surface layer. It is composed of highly oriented recrystallized PFA chains that have be

The PFA (120 × 10-6 /°C) has a different coefficient of thermal expansion (CTE) than the metal core (usually a nickel-chromium resistance wire, 17 × 10-6 /°C) in a PFA heat rod, wh

90% formic acid (HCOOH) at 100°C is a reducing environment which somewhat passivates titanium. The corrosion behaviour is strongly affected by the water content in the acid. At 5% water (95% formi

Titanium heaters are operating in a near-passive regime at 100 deg C in 90% formic acid. The mode of the material deterioration is decisively determined by the water content in the acid. At 5% water (

Titanium immersion heaters are protected from oxidation by a nitrogen blanket in a eutectic salt bath at 300°C. However, if oxygen is available in the nitrogen blanket oxygen may permeate to the t