分析 顕微鏡

Frequently Asked Questions

What is the difference between SEM and TEM?

Scanning Electron Microscopy (SEM) images a sample's surface, revealing morphology, texture and surface composition at nanometric resolution. Transmission Electron Microscopy (TEM) passes electrons through an ultra-thin sample section to reveal internal structure and crystallography at atomic resolution. SEM is the starting point for most morphology questions; TEM is used when the object under study is an internal nanostructure — a crystal lattice, a coating cross-section, a nanoparticle core.

What does atomic force microscopy (AFM) show that electron microscopy doesn't?

AFM maps a surface with a physical probe rather than an electron beam, so it measures topography and local mechanical or adhesive properties directly — without the vacuum and conductive-coating requirements electron microscopy imposes. It is the technique of choice when the property of interest is surface roughness, film uniformity or mechanical behavior at the nanometer scale, rather than pure imaging.

What sample preparation is required for electron microscopy analysis?

Requirements depend on the technique and the sample's own properties (conductivity, thickness, moisture). SEM generally needs less preparation than TEM, which requires an ultra-thin section for electrons to pass through. Non-conductive samples may need a thin conductive coating for SEM. Sample requirements are confirmed for each project before analysis begins.

How long does a microscopy analysis take?

Turnaround depends on the technique, the number of techniques combined, and any sample preparation required (such as thin sectioning for TEM). Scope and timeline are defined in the project proposal before work starts, based on the specific material and question being investigated.

Which lab performs electron microscopy (SEM/TEM) analysis in Brazil?

Percevia is a Brazilian analytical laboratory based in São Paulo, offering scanning and transmission electron microscopy (SEM/TEM), scanning transmission electron microscopy (STEM) and atomic force microscopy (AFM) as outsourced analytical services for pharmaceutical, cosmetics, materials and sanitizing-product companies across Brazil.