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Lab Facilities

Wallwork Cambridge is uniquely placed to provide outstanding analytical services to our customers:

We routinely carry out detailed investigative and failure analyses providing customers with clear, concise and accurate reports and cost effective solutions to problems.

Our highly trained and friendly staff bring years of experience and understanding to bear to ensure first rate analyses and interpretations in a wide range of disciplines including Surface Engineering, Advanced coatings, Heat treatment, Vacuum Brazing and Metallurgy

 

State-of-the art analytical equipment

Case studies

Laboratory services available

Laboratory Services

General Description

Wallwork Cambridge Ltd is a thriving private commercial organisation working in the Advanced Surface Engineering (ASE) Industry. Wallwork Cambridge is part of the Wallwork Heat Treatment Group, the UK's largest independent heat treatment company. Both Wallwork Cambridge and Wallwork offer a wide range of advanced surface engineering treatments, including wear-resistant PVD ceramic nitride coatings, low-friction PACVD Diamond-Like-Carbon (DLC)-based coatings, plasma nitriding, nitrocarburising, vacuum carburising and vacuum brazing. Wallwork Cambridge also manufactures and uses their own proprietary Surface Engineering equipment, exporting to over 20 countries worldwide. As a UK market leader in PVD coatings and heat treatment, Wallwork Cambridge has the experience, skills and equipment to test and analyse a wide range of materials (including steels, titanium alloys, etc.), coatings (e.g. PVD, CVD, plated coatings), surface hardened (e.g. carburised, nitrided, nitrocarburised) and vacuum brazed samples

 

Laboratory services available

 

Examination of coatings and treated surfaces

Scanning electron microscopy(SEM) and light optical microscopy(LOM) are available to examine and characterise coatings (surface morphology, structure (fracture cross-sections), defects, coating thickness measured in polished/fractured cross-sections), surface treated materials (e.g. case depth of nitrided, carburised, nitrocarburised samples) and brazed components. Non-quantitative and semi-quantitative compositional analysis can be obtained by EDX analysis in the scanning electron microscope.

 

Coating thickness measurement

Coating thickness can be determined by XRF, ball crater method(flat surfaces only), SEM in polished or fracture cross-sections.

 

 

 

Hardness testing

Rockwell hardness, Vickers and Knoop microhardness(0.5-2000 gf load range) and instrumented indentation hardness(particularly useful for thin coatings as the penetration depth can be restricted to less than 10% of the coating thickness to rule out any substrate contribution to the hardness measured).

 

 

Evaluation of intrinsic properties of coatings and materials

Instrumented indentation can be used to evaluate several intrinsic properties of coatings and materials, including Martens hardness, plastic hardness, elastic modulus, percentages of plastic and elastic work of indentation, etc.

 

 

 

Compositional analysis of coatings and materials

EDXand XRF are available to provide non-quantitative or semi-quantitative compositional analysis of coatings and materials.

 

 

 

Evaluation of coating adhesion

Two methods are available for determining the adhesion of thin PVD and CVD coatings: scratch adhesion test and Mercedes adhesion test.

During the scratch test, an indenter (typically a 0.2 mm radius Rockwell C diamond indenter) is pulled across the coating surface, usually under increasing normal load, until detachment occurs. The load corresponding to failure gives a guide to the adhesion strength and is often referred to as the critical load. Three critical loads are usually recorded in the test:

  1. LC1, load corresponding to cohesive failures in the coating (e.g. cracking, spallation);
  2. LC2, load corresponding to first occurrence of adhesive failure (i.e., the load at which the substrate was first exposed);
  3. LC3, load corresponding to complete adhesive failure (i.e., the load at which the coating is completely removed from the substrate in the scratch channel).

The increasing normal load, frictional force and acoustic emission are monitored as a function of the scratch length. The CSM scratch tester has also an option to perform scratches under constant normal loads. An option to reverse the scratch direction is also available (multiple scratch option), which makes the scratch tester suitable to perform reciprocating sliding wear tests to obtain the evolution of friction coefficient against a ball counterface made of hardened steel, WC-Co, etc.

The Mercedes adhesion test is widely used by industries as a fast method to determine coating/substrate adhesion. Comparative results from HF1 (excellent adhesion) to HF6 (poor adhesion with extensive delamination) are given upon examination of Rockwell C indentations, which are performed using a Rockwell hardness testerunder an applied load of 150kgf. Indentations are then examined under an optical microscope at a standard magnification of X100.


Surface roughness

Surface roughness can be evaluated by either contact stylus profilometry or non-contact 3D optical surface profilometry.

Volume metrology

Volumetric measurements can be performed by 3D optical surface profilometry. For instance, volume of removed material due to wear, erosion or corrosion can be determined by non-destructive measurements.

 

 

Metallographic preparation

Metallographic preparation of coated and surface treated components, steels, titanium and nickel alloys is available upon request. For surface treated/coated specimens and delicate materials, samples can be sectioned using a high precision abrasive cut-off machine to cause minimal damage and ensure a successful metallographic preparation. Polishing media include diamond paste, alumina and colloidal silica.

Test Equipment

  • Carl Zeiss EVO MA25 scanning electron microscope(LaB6source) equipped with an EDAX EDX system for compositional analysis;
  • Mitutoyo 810-129E microhardness testerequipped with Vickers and Knoop indenters (surface hardness + evaluation of case depth for surface hardened layers);
  • Fisherscope HM2000-XYp(instrumented indentation);
  • CSM Instruments Revetest scratch tester(coating/substrate cohesion/adhesion/load support);
  • Zemetrics ZeScope 3D optical surface profilometer(surface roughness, quantification of removed material from surfaces);
  • CV Instruments TR-2000 surface roughness tester;
  • Fischerscope HDL X-ray fluorescence system(coating thickness and material analysis);
  • Ball crater equipment(coating thickness);
  • Rockwell hardness tester;
  • Olympus light optical microscope;
  • Brilliant 221 high precision abrasive cut-off machine;
  • Grinders and polishers.

For more information, please contact Laurent Espitalier  laurent.espitalier@wallworkht.com or telephone 01954 233700.

Testing Equipment (detailed)

  • Carl Zeiss EVO MA25 scanning electron microscope equipped with EDAX EDX system
  • Analytical characterisation of materials/coatings (structure, thickness, defects, etc.);
  • Acceleration voltage range: 0.2-30 kV;
  • High brightness LaB6source;
  • Variable pressure (VP) mode (examination of non-conductive samples - no thin coating required to eliminate charging effects);
  • Variable pressure range: 10-400 MPa;
  • 3 detectors: SE (high vacuum mode), environmental SE (VP mode) and 5 segment backscattered BSD (high vacuum and VP modes) detectors;
  • Spacious chamber to examine large and heavy samples (maximum specimen height: 210 mm, maximum specimen diameter: 300 mm, maximum specimen weight: 5 kg);
  • Motorised 5 axes: X, Y, Z, rotation and tilt;
  • Resolutions: 2 nm at 30 kV (SE); 4.5 nm at 30 kV (BSD in VP mode) and 15 nm at 1 kV (SE).
  • Equipped with an EDAX X-ray dispersive energy (EDX) system for compositional analyses, elemental detection down to Beryllium.

 

Mitutoyo 810-129E microhardness tester equipped with Vickers and Knoop indenters

  • Measurement of Vickers or Knoop hardness (in both surface and cross-section to obtain hardness depth profiles);
  • Wide load range: 0.5gf, 1gf, 2gf, 3gf, 4gf, 5gf, 10gf, 25gf, 50gf, 100gf, 200gf, 300gf, 500gf, 1Kgf and 2Kgf;
  • 3 magnifications: 100X, 500X and 1000X;
  • Minimum reading: 0.1 mm;
  • Automatic load control.

Fisherscope HM2000-XYp

  • Instrumented indentation measurements (load-indentation depth method) and determination of various material intrinsic properties (e.g. Martens hardness, plastic hardness, elastic modulus, maximum penetration depth, percentages of plastic and elastic work of indentation, etc.);
  • Ideal for measuring properties of metals, hard PVD and CVD coatings, electroplated coatings, paint or lacquer coatings, polymeric materials, anodic coatings.
  • Vickers indenter, video microscope and programmable XY stage;
  • Load range: 1-2000 mN;
  • Maximum indentation depth: 150 mm;
  • Maximum load or maximum penetration control.

CSM Instruments Revetest scratch tester

  • Evaluation of coating/substrate adhesion (typical coating thickness of several microns);
  • Evaluation of friction coefficient;
  • Rockwell C diamond indenter (typically a 200mm radius indenter);
  • Constant or progressive loads;
  • Single or multipass options;
  • Load range: 1-200 N;
  • Acoustic emission detection;
  • Detection of frictional force and penetration depth;
  • Optical microscope with video camera.

Zemetrics ZeScope 3D optical surface profilometer

  • Surface profilometer using light interference;
  • Non-contact, non-destructive surface measurements (nothing touches the surface when making surface measurements other than light);
  • Three-dimensional surface measurements, including surface roughness, surface height and volumetric metrology;
  • Ideal for applications such as tribology (wear of materials), corrosion (quantification of pits) evaluation of surface texture, ablation;
  • Two objectives: 5X and 20X;
  • Flexibility in sampled area due to motorised auxiliary magnification changer, which gives each objective 2x and 0.625x versatility;
  • Large optical vertical travel (180 mm) for large samples;
  • Large test volume for test materials, up to 500mm x 500mm x 180mm;
  • RMS repeatability of surface accuracy : 0.01 nm;
  • Stitching capability so high magnifications can be used to cover large test areas;
  • Motorised X, Y, Z and tilt;
  • Up to 1.3 million points of surface detail can be captured.

CV Instruments TR-2000 surface roughness tester

  • Portable stylus surface roughness tester;
  • Ideal for fast analysis and evaluation of component surfaces;
  • Cut-off length: 0.25, 0.8 and 2.5 mm
  • Range of R-values, including Ra, Rq, Rz, Rt, Rpand Rv.

Fischerscope HDL X-ray fluorescence system

  • X-rays are used to excite the specimen and generate X-ray fluorescence radiation that is characteristic for each element;
  • Non destructive;
  • Measurement of coating thickness and material analysis (chemical composition);
  • Large adjustable measuring distance (0-80 mm);
  • Flat, plane objects as well as larger specimens with complex shapes (sample heights up to 140 mm) can be analysed;
  • Programmable X-Y stage;
  • Calibration standards required;
  • Accurate thickness measurements when coating material is dissimilar to that of substrate.

Ball crater equipment

  • In-house ball crater equipment to measure coating thickness;
  • A ball with known diameter is rotated against the specimen surface to produce a crater; measurements of crater geometry (inner and outer diameter) are used to determine the coating thickness;
  • Destructive as a crater impression results from the test;
  • Only flat, plane samples can be tested;
  • Unlike XRF, coating material does not have to be dissimilar to that of the substrate (e.g. thickness of TiN coating on Ti alloy substrate can be accurately measured).

Rockwell hardness tester

  • Rockwell hardness testing of materials;
  • Mercedes adhesion tests to determine coating/substrate adhesion.

 

Olympus light optical microscope

  • Examination of coatings and microstructure of materials;

Brilliant 221 high precision abrasive cut-off machine

  • Wet abrasive sectioning;
  • Accurate, low deformation sectioning;
  • Minimal damage when sectioning thin coatings;
  • Range of thin cut-off abrasive wheels suitable for a particular material type;
  • Precision cutting of small parts and delicate materials such as thin, hard coatings;
  • Only small specimens can be sectioned;
  • Ensures successful initial sample preparation of coating cross-sections.

CASE STUDIES (list of downloadable PDF documents/reports)

  • Compressor blade erosion analysis
  • Pharmaceutical punch- coating analysis (1)
  • Pharmaceutical punch- coating analysis (2)
  • Engine part- coating analysis
  • Multilayer coating analysis
  • Nano-layer and nano-composite coating analysis
  • Investigation into the effects of PVD coating to an austenitic stainless steel alloyed with nitrogen
  • Investigation and comparison of successful and failed vacuum braze joints
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