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This paper aims to analyze the corrosion and corrosion inhibition of N80 in 10 per cent HCl + 8 per cent fluoroboric acid (HBF₄) solution for acidizing operation.

The corrosion rate, kinetic parameters (Ea, A) and thermodynamic parameters (ΔH, ΔS) of N80 steel in fresh acid and spent acid, 10 per cent HCl + 8 per cent HBF₄, 10 per cent HCl and 8 per cent HBF₄ solutions were calculated through immersion tests. The corrosion and inhibition properties were studied through X-ray diffraction and electrochemical measurements. The corrosion morphology of the corrosion product was examined by scanning electron microscopy (SEM).

The results demonstrated that the spent acid was the main cause of acidification corrosion, and the HBF₄ would cause serious corrosion to N80 steel. The results showed that the N80 steel was more seriously corroded in the spent acid than in fresh acid, and the hydrolysis of HBF₄ accelerates the dissolution process of N80 steel anode to control the corrosion reaction. The results showed that the acidification will definitely cause serious corrosion to the oil tube; therefore, necessary anti-corrosion measures must be taken in the acidification process.

The results showed that acidizing the formation with 10 per cent HCl + 8 per cent HBF₄ will definitely cause serious corrosion to the oil tube, especially when the spent acid flows back. Therefore, necessary anti-corrosion measures must be taken in the acidification process, especially in the spent acid flowback stage.

12 mil pitch processing is achievable with solder paste. It may also be the limit of solder paste printing technology, mainly due to the scooping problem associated with thin stencils. With decreasing pitch size, both smear and insufficiency rate increase. Tapering of stencil aperture helps thick stencil prints, but has an adverse effect on thin stencil printing. Apertures with orientation parallel to squeegee movement result in a higher print defect rate. Overall, the use of fine powders is the most effective means to meet most challenges. It helps in achieving high performance in printability, tack and non‐slump, with acceptable trade‐offs in rheology and tack time. Solder balling may be the primary drawback. The problem may be resolved by using inert reflow atmosphere or via flux chemistry improvements. A metal load of 90.5 to 91% seems to be the optimum for most properties.