Krypton Low-Surface-Area Analyzer for Thin Films and Flat Substrates

What is the Krypton Low-Surface-Area Analyzer for Thin Films and Flat Substrates?

A volumetric analyzer configured for krypton adsorption at 77 K with a low-volume manifold and a sensitive low-range transducer. It measures total areas as low as 0.05 m², so it suits thin films, sintered ceramics, fuel pellets, coated substrates and other low-area samples.

Overview

With nitrogen, the signal from samples below 1 m² of total area is too small to separate from the gas in the free space. Krypton has a saturation pressure of only about 2.5 torr at 77 K, so the same number of adsorbed molecules produces a far larger relative change in pressure. This variant minimizes manifold volume, uses a pressure transducer of 1 or 10 torr full scale with high resolution, and applies corrections for the solid-phase saturation pressure of krypton. The BET analysis is done at 0.05 to 0.30 relative pressure, following ISO 9277 and ASTM D5604 style practice. Sample tubes are designed with filler rods to reduce dead volume. Typical repeatability is within 3 to 5 percent at low areas, larger than for nitrogen on high-area powders.

How does it work?

These analyzers expose a degassed solid to an adsorbate and measure how much is taken up. In static volumetric physisorption, known doses of nitrogen, argon or krypton are admitted to a manifold and sample tube at 77 K or 87 K, and the pressure drop after equilibration gives the adsorbed volume. Isotherms are analyzed with BET for surface area, t-plot and DFT methods for micropores, and BJH for mesopores. Gravimetric systems weigh the sample directly while vapor pressure is controlled. Chemisorption analyzers dose hydrogen, CO or oxygen at elevated temperature and use thermal conductivity detection for temperature-programmed reduction and desorption. Key components are vacuum pumps, pressure transducers, a cryogenic bath or furnace, and analysis software.

What are the key features?

• Krypton-specific low-volume manifold to reduce free-space error
• High-resolution 1 or 10 torr transducer for low pressure accuracy
• Solid krypton saturation pressure correction in the software
• Sample tubes with filler rods to reduce dead volume
• Automated degassing with heating to 350 °C
• Report of BET area to 0.05 m² total surface

What are the technical specifications?

A typical krypton low-surface-area analyzer for thin films and flat substrates configuration offers adsorbate of Krypton at 77 K, minimum total surface area of ≥ 0.05 m², surface area range of 0.001–20 m²/g, transducer range of 1 torr and 10 torr, transducer accuracy of ±0.15% of reading and relative pressure for BET of 0.05–0.30. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Krypton Low-Surface-Area Analyzer for Thin Films and Flat Substrates is used in thin film and coating surface area, nuclear fuel pellet and ceramic analysis, flat wafer and substrate characterization and low-area pharmaceutical crystals. Across the wider Surface Area Analyzers class, laboratories also deploy it for catalyst and support characterization, battery electrode powder analysis and activated carbon and adsorbent testing.

Which standards and certifications apply?

Relevant standards and methods include ISO 9277, ISO 15901-2, ISO 15901-3, ASTM D3663 and ASTM D4365. Certification candidates for this model are CE and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Sample degassing is the main source of error; select temperature and time so that moisture and volatiles are removed without changing the structure, and weigh the sample after degassing. Use adequate sample mass to provide at least 1 m² of total surface area, or 0.05 m² with krypton. Check free-space calibration and leak rates regularly. Ensure a reliable supply of high-purity gases, typically 99.999 percent, and monitor liquid nitrogen levels. Verify performance with certified reference materials of known surface area. Place the unit on a stable bench with ventilation for cryogenic and hydrogen work, and follow local rules for compressed gas cylinders.

How do I select the right Krypton Low-Surface-Area Analyzer for Thin Films and Flat Substrates?

Select this variant when samples have less than about 1 m² total area, or when the specification is written in cm² or m² for a whole article rather than per gram. A standard nitrogen analyzer with a krypton option may be adequate for occasional use. In an RFQ, specify sample mass range, krypton purity, sample tube size and whether reporting follows ISO 9277.

How does it compare with other Surface Area Analyzers variants?

Decide first what must be measured. Surface area and mesopore size of powders, catalysts and electrode materials suit a volumetric physisorption analyzer; micropore work requires turbomolecular pumping and low-pressure transducers. Very low area films and substrates need krypton capability. Water or solvent uptake calls for a gravimetric vapor sorption analyzer. Metal dispersion and acid site measurements need a chemisorption system with a furnace and detector. Hydrogen and methane storage research needs a high-pressure sorption analyzer. Compare the number of analysis ports, degassing stations, pressure range, transducer accuracy, liquid nitrogen consumption and compliance with ISO 9277 and ISO 15901-2 when specifying.