Unibody of the iPhone 17 Pro Max in an exclusive Material Analysis – Why scratches can occur and dents are easily possible! | Update

Update from 03.11.2025 – Updated the LIBS analysis with 16 deeper shots to decide between 5000 or 7000 alloy.

Today we’re getting down to the nitty-gritty, or rather: the case. The unibody of the iPhone 17 Pro Max with its 1 TB of memory lies under my Keyence VHX7100 with the AE-300, as if it were the most normal thing in the world to chase a four-digit expensive smartphone through high-resolution microscopes and spectrometers in the six-digit range. Childlike curiosity meets grown-up toys here, because once you’ve started digging through the microstructures of an alloy, you won’t be able to get away from it any time soon. It’s a mixture of “What will happen if I take a closer look?” and “After all, what’s the point of having all this equipment in the lab?”. If you’ve got it, you’ve got it – and if you’ve got it, take a closer look.

Because aluminum is not just aluminum, and that is where things get interesting. With the iPhone 17 Pro Max, Apple has moved away from the multi-part titanium frame to a unibody made of aluminum. At first this may sound unspectacular, but it is not when you know that aluminum can behave very differently depending on the alloy: sometimes soft and malleable, sometimes hard and brittle. In the graphics card industry, blends with silicon and copper are often used because they are hard, durable, and easy to cast, but they also have disadvantages in terms of corrosion. The new iPhone, however, shows a completely different approach.

What triggered me were the countless reports on social media in which owners of the new iPhones complain about scratched, nicked, or even already dented housings. As a potential victim myself, I could not ignore this, on the contrary, it made me all the more eager to take a closer look. That is why today there will not just be a simple material analysis, which would be almost too easy, but also an explanation of why exactly what happened actually happened. Amusing is the observation that people are willing to spend 2000 euros on a smartphone but skimp on a simple case for 20 euros. Anyone using it without a case quickly risks unsightly marks on the expensive unibody. With the new iPhone, it has become harder to proudly present the flawless housing of the latest status symbol at the next get-together, because without protection showing off has become riskier than ever before.

That is exactly why I want to know what Apple has actually mixed together as “aluminum.” LIBS stands for Laser-Induced Breakdown Spectroscopy and is an analytical method for fast, low-destructive material identification. It is based on a highly energetic, short laser pulse being focused on the surface of the sample material. This creates an extremely small plasma bubble because the material is locally vaporized and ionized. This plasma emits light in a characteristic spectrum as it cools down. Each chemical element has certain emission lines that act like a fingerprint. By recording and analyzing these lines with a spectrometer, the qualitative and quantitative composition of the material can be determined. And that is exactly what we will do now.

Rough shell, hard core? The surface analysis

The first image clearly shows that we are no longer just dealing with the base material of the high-magnesium aluminum alloy, but with the top layer, i.e. the surface treatment. The spectral analysis shows a composition of around 53.5 percent oxygen, 30.3 percent aluminum, 13.4 percent carbon and 2.8 percent hydrogen. This is a typical pattern for an anodized surface that has also been organically modified or sealed.

The very high oxygen concentration clearly indicates the presence of aluminum oxide, which was deliberately built up as a protective layer using the anodic oxidation process. The layer consists of porous Al₂O₃, which can be colored with dyes or inorganic salts. In the case of Apple, sealing is usually carried out after anodizing, in which the open pores are closed by hydrating the oxide to boehmite (AlO(OH)) or by chemical additives. The measured hydrogen content indicates precisely this process, in which hydroxide groups are deposited in the layer.

The detectable carbon content indicates an organic coating or dye infiltration. In practice, Apple usually uses organic dyes for dark shades, which are introduced into the pores of the anodic layer and then fixed. These organic residues are then measurable, even if they are only a few nanometers deep. Alternatively, it could be a thin polymer-based protective sealant that is applied afterwards to increase scratch resistance and reduce fingerprints.

The surface of my iPhone 17 Pro Max consists of a classic hard anodization of the underlying alloy, which has been modified by dye infiltration and chemical sealing. The advantages are a significantly higher scratch resistance compared to the raw material, a stable color and very good corrosion resistance. Disadvantages remain the limited thickness of the oxide layer (typically 10 to 20 µm for consumer electronics) and the fact that hard foreign bodies such as keys or sand particles can mechanically break through the oxide layer. This also explains why scratches and nicks occur in practice despite high-quality surface treatment: The anodized layer reliably protects against abrasion and corrosion, but is not indestructible. As soon as the oxide layer is penetrated, the softer base metal underneath is revealed and the damage is immediately visible. Why it is so soft, you will find out in a moment.

The unibody in the material test

I had to update my first review, because I made a longer series of shots into the depth, not only an averaged measurement with 5 shots. I used now another place in the body and measured again, but with 16 single shots in the depth. The measurement series shows similar characteristics as before, but with a much clearer lateral distribution because sixteen spatially separated single spots were ablated on the same freshly prepared surface instead of collecting multiple pulses in a single crater. This reveals the lateral inhomogeneity of the near-surface zone rather than only the depth profile. The table lists the relative mass fractions of O, Al, C, H, Mg and Zn, where C and H mainly originate from organic residues, adsorbed films or background effects and therefore are not relevant for alloy identification. The decisive parameters are the ratios of aluminium to magnesium and zinc, as well as the oxygen content as an indicator for remaining oxide or hydroxide phases.

Spots 0 to 3 and 12 to 14, which still show roughly 50 to 75 percent aluminium and a clearly double-digit oxygen content, are located in the transition region between oxide layer and base material. Magnesium and zinc signals are low or absent because the laser only partially penetrates the oxide layer and the first few hundred nanometres are still dominated by Al₂O₃, MgO and hydrated surface products. The large variation in the oxygen values (16 to 60 percent) is caused by local roughness and different oxide film thicknesses. Some craters reach slightly deeper, others remain at the surface, which explains the complementary fluctuation of aluminium.

From spots 4, 5, 6, 7 and 8 onwards, the metallic matrix becomes clearly visible, because oxygen drops to almost zero and aluminium rises above 80 percent. Magnesium and zinc now appear reproducibly, although the lateral distribution varies strongly. Spot 6 shows about 100 percent Mg, which of course does not represent the real bulk composition but indicates that the pulse hit an intermetallic phase or a segregated Mg-rich precipitate, as found in Al-Zn-Mg systems (η-phase, MgZn₂). The same applies to spot 8, where 100 percent Zn is reported. Again, this is a normalised value resulting from a locally zinc-rich particle rather than the true alloy composition.

These extreme Mg and Zn values confirm the presence of segregated precipitates typical for 7xxx alloys. A 5xxx alloy would contain magnesium, but not such pronounced zinc segregation. Likewise, 6xxx alloys would show Mg together with Si (as Mg₂Si), but no zinc.

The remaining matrix spots (for example 4, 5, 7, 9, 10, 11) show more moderate compositions with aluminium between 70 and 90 percent, magnesium between 3 and 15 percent and zinc between 3 and 6 percent, which fits well into the range of a low copper 7xxx alloy, typically 7005 or 7020. Since none of the spectra show copper lines at around 324 or 327 nm above background level, 7075 can be ruled out, because that alloy contains at least about 1.2 percent copper, which would be easily detectable. The absence of Cr, Mn or Zr signals also points more toward 7005 than 7020, because 7020 normally contains 0.2 to 0.5 percent Mn, which would be visible in LIBS if present. 7005 usually contains only trace amounts of Zr for grain refinement, often below 0.15 percent, potentially below the detection limit or not included in the export.

The heterogeneous single-spot values are therefore explained partly by varying oxide removal depth and partly by true microstructural segregation of precipitates. The spots showing almost pure Mg or Zn are analytically useful as proof of these segregations, but they must not be used for averaging the matrix composition. For this, the more stable spots (4, 5, 7, 9, 10, 11) should be considered. Combining them yields a composition of roughly 85 percent aluminium, 8 to 10 percent magnesium and 4 to 5 percent zinc, which meets the specifications of alloy 7005, whereas 7020 typically contains slightly less Mg and requires Mn as an accompanying element. The characteristic near-surface Mg enrichment is also documented for 7005, which tends to form Mg-rich grain boundary regions after heat treatment.

Therefore, the material can be identified as alloy 7005 with a pronounced oxide and segregation-affected surface zone. The strong fluctuations in O, Mg and Zn from spot to spot are fully expected and result from both surface oxidation and microstructural heterogeneity. For a final quantitative statement, a multi-pulse ablation (for example 20 pulses per spot) with rejection of the first five cleaning pulses and internal normalisation to the Al line would be recommended, optionally combined with light mechanical pre-cleaning or mild ion etching to further reduce the oxide layer.

Comparison of 5000-Series and 7005 Aluminium Alloy

Conclusion

The bottom line is that the whole mess with Keyence, AE-300 and LIBS only shows what many iPhone owners are currently experiencing on their own devices: Apple relies on a high-magnesium aluminium alloy for the iPhone 17 Pro Max, which is light, corrosion-resistant and easy to anodize, but also has its limits. The anodized oxide layer reliably protects against corrosion and makes the casing more resistant, but if a bunch of keys or a grain of sand is involved, the perfect surface is no more. Then the soft base metal quickly shows through and the unsightly dents or notches appear.

The analyses therefore explain very well why the cases scratch and dent, but do not change the fact that it is still hotly debated on social networks. It remains amusing that many people are prepared to pay 2,000 euros for a smartphone, but save money on a simple case for 20 euros. Personally, I have already learned this lesson and have long since treated myself to a case – not for fashion reasons, but quite simply out of common sense. If you’ve got it, you’ve got it, and if you’re clever, you’ll protect it. Then you’ll have it for longer 😀