Cold spray coatings form only when particles clear a critical impact velocity, a threshold set by material properties, particle size and morphology, and native oxide condition. This article looks at what powder-side QC can flag before a spray trial, and where it stops short of predicting deposition efficiency.
Triboelectric separation turns contact electrification from a handling hazard into a deliberate sorting mechanism. This article covers how material pairs are selected by charge polarity, what feed moisture and particle size do to separation efficiency, and where the technique sits relative to density and optical sorting.
FDA's proposed hub-and-spoke registration rule treats geographically separate manufacturing units as one establishment. The registration paperwork is new; proving that blend uniformity, granulation endpoints, and moisture behavior actually match between sites is the older, harder problem.
Powder spreading in powder bed fusion is a recoater-powder interaction shaped by cohesion, particle size distribution, and particle shape. This article maps streaking, short-feeding, and layer non-uniformity back to their underlying mechanisms and separates powder-driven causes from blade wear and spreading speed.
As aerospace metal additive manufacturing capacity expands, more reused powder is going back into qualified builds. The virgin-to-reused blend ratio decision depends on PSD shift, satellite formation, and morphology drift, and cannot be settled by a single powder check disconnected from the part's stress state.
Dense-phase and dilute-phase pneumatic conveying create different particle contact mechanics, and the resulting attrition and segregation risk depends on velocity, solids loading ratio, and the powder's own attrition sensitivity, not on a fixed assumption about which mode is gentler.
Cement fineness is not a single number. Blaine surface area, particle size distribution, grinding aid chemistry, and moisture history each pull on hydration reactivity in different ways, and a fineness specification that ignores any one of them will eventually let a bad batch through.
Geldart classification, minimum fluidization velocity, bubble dynamics, droplet-to-particle size ratio, and permeability all determine whether a fluidized bed process delivers controlled granule growth, uniform coating, or consistent drying at production scale.
Process analytical technology combined with machine learning is changing residual moisture control and yield prediction in pharmaceutical and food spray drying. The gains are real but bounded, and the off-line test panel has not been replaced.
Sintered contacts, additive manufactured heat exchangers, EV motor components, and conductive pastes each require a different copper powder. This article explains why morphology, particle size distribution, oxygen content, and packing density are engineering variables, and how to specify them correctly for electrification applications.
